Navitron Renewable Energy and Sustainability Forum

SOLAR THERMAL => Solar Thermal Systems => Topic started by: chris wills on May 15, 2019, 01:04:56 PM



Title: Solar thermal not circulating
Post by: chris wills on May 15, 2019, 01:04:56 PM
We have a solar thermal system, 30 thermomax tubes into a cylinder, for our hot water only, backed up with an immersion heater.
It has stopped working over the last few weeks, the water does not circulate.
The pump is fine, no issues with that, is there some sort of air valve on the tubes that maybe causing a lock of some sorts?
Pressure is fine.
Any first thoughts, I suspect a blockage somewhere.


Title: Re: Solar thermal not circulating
Post by: chris wills on May 28, 2019, 09:10:51 PM
Is there a way I can flush the tubes on the roof only?


Title: Re: Solar thermal not circulating
Post by: ecogeorge on May 28, 2019, 11:24:52 PM
How do you know its not circulating -silly q  but you haven't said.
Is collector temp v  high.
What happens if you run the pump manually ?
more info please .


Title: Re: Solar thermal not circulating
Post by: Westie on May 29, 2019, 11:50:42 AM
Is there a way I can flush the tubes on the roof only?

It's pretty unlikely to be a blockage in the collector, they're generally 22mm straight through. As George said the question to resolve is whether there is circulation , quite a hard thing to prove in most solar thermal systems. The pump is where i would start, it can be energised and quietly buzzing away but not actually spinning .eg stuck. Some pumps allow you to remove a centre screw and see if shaft is spinning but be careful and only work on the system when it's cold and close the valves either side before you take the screw plug out (if you have one).

youtu.be/QFYnwT08aCQ



Title: Re: Solar thermal not circulating
Post by: chris wills on June 10, 2019, 04:41:07 PM
Thanks for the feedback, I actually have 30 tubes which I have now corrected in my first post.
The pump is working fine, I did inspect through the large screw on it and was fine, sometime ago. In any case I replaced the pump just to see how it was and no change.

In answer to some of the questions:

1. Tubes are Thermomax DF100
2. At its highest the roof temp reaches about 102 degrees, but the return pipe is all but luke warm, which indicates to me non-circulation?
3. All the electrics are OK, pump come on when it should
4. When you say manually run the pump, do you just mean switching it on myself? whats the difference between auto and manual in this case?

I was thinking issue with the tubes?
I really need help here to rectify it as I am living on an immersion heater booster to the storage tank, not the best.



Title: Re: Solar thermal not circulating
Post by: Iain on June 10, 2019, 04:49:17 PM
Hi
If the pump is fine, I would think it is either air, however if the pressure in the system is good how did the air get in, so possibly unlikely.
Is there a non return valve in the system? If so could that be stuck?
My system has an upstand in the pipe in the loft with a manual vent valve on. So mine is easy to check for air. Has your a bleed salve in the loft?

Just a quick question, how did you vent the air after changing the pump?


Iain


Title: Re: Solar thermal not circulating
Post by: daveluck_uk on June 10, 2019, 07:55:48 PM
if it was all working and then just stopped and the pump is OK....it'll be air...undo bleed screw, let out the air,  top up with antifreeze, re-pressurise, jobs a good un.

Depending on your skill set you might need to get someone in!


Title: Re: Solar thermal not circulating
Post by: todthedog on June 10, 2019, 09:07:18 PM
A garden sprayer is great for re-pressurising


Title: Re: Solar thermal not circulating
Post by: chris wills on June 11, 2019, 07:52:26 AM
When the pump was changed, I shut off the 2 valves either side of it before removal.
The air bleed is near to the pump, but could there be one on the roof too? Maybe this would do it? Where would it be on the Thermomax tubes?
Where could the non-return valve be?
Many thanks for your feedback guys, food for thought.

Also do you know anyone in South Wales area who could look at it?



Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 03:40:25 PM
Heres an image of my pump setup, I realise its not all connected through a pump station.
Does this pump need to be fitted vertically or is it OK as it is?


Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 03:41:17 PM
A garden sprayer is great for re-pressurising


How do you use a garden sprayer to pressurise?


Title: Re: Solar thermal not circulating
Post by: Iain on June 16, 2019, 03:55:54 PM
Hi
You have 2 options for re pressurising.

Mains cold water via a filling loop (same as a boiler filling loop) only suitable if your mains cold is nearby.

Or a garden sprayer with an adaptor on the end to attach to a filling loop. This allows you to add an inhibitor and re pressurise the system.

I do a bit of both.
The garden sprayer is used to inject the solar inhibitor, I then use the mains to take the pressure up to 1 bar.

Iain


Title: Re: Solar thermal not circulating
Post by: Philip R on June 16, 2019, 04:07:38 PM
Chris,
Your pump is incorrectly mounted.
The shaft should lay horizontally as per the instructions. The pump bearings are not designed as thrust bearings, so you will damage the pump quickly like this.
Isolate the pump, loosen the 52mm unions. Rotate till shaft horizontal and junction box either at sides or on top, but not bottommost.
Philip R


Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 04:32:09 PM
Chris,
Your pump is incorrectly mounted.
The shaft should lay horizontally as per the instructions. The pump bearings are not designed as thrust bearings, so you will damage the pump quickly like this.
Isolate the pump, loosen the 52mm unions. Rotate till shaft horizontal and junction box either at sides or on top, but not bottommost.
Philip R

Hi Phillip,

Can you explain more please, what do you mean shaft horizontal? I did read that the bleed valve should point downwards for air purposes, is this the case?
Thanks for your feedback.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 04:33:17 PM
Hi
You have 2 options for re pressurising.

Mains cold water via a filling loop (same as a boiler filling loop) only suitable if your mains cold is nearby.

Or a garden sprayer with an adaptor on the end to attach to a filling loop. This allows you to add an inhibitor and re pressurise the system.

I do a bit of both.
The garden sprayer is used to inject the solar inhibitor, I then use the mains to take the pressure up to 1 bar.

Iain

Hi Iain,

How do you do this? Do you have any pictures?


Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 05:56:07 PM
Is this now correct?
Another thing.....although the previous pump setup did not work correctly, can anyone tell me if the head unit onto the pump body is correct?
Is it the right way around or have I messed it up?

Is elbows and connection to close to the pump a bad thing?

I would ideally like to connect the pump up vertically, I have the room to fit it, anyone think this is a good idea?



(https://i.postimg.cc/XGgcBGP3/IMG-1039.jpg) (https://postimg.cc/XGgcBGP3)

(https://i.postimg.cc/RJV17Crt/IMG-6124.jpg) (https://postimg.cc/RJV17Crt)

(https://i.postimg.cc/3WKZ51yw/IMG-8411.jpg) (https://postimg.cc/3WKZ51yw)


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 16, 2019, 06:33:00 PM
No rotate it 180 degrees from where it is now. Control box wants to be on the top so water can't go in it.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 06:51:01 PM
Is this now all correct?


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 16, 2019, 07:24:37 PM
yes


Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 07:26:57 PM
thanks for that, now need a bit of sun to try it out


Title: Re: Solar thermal not circulating
Post by: Iain on June 16, 2019, 07:47:04 PM
Hi

Quote
Hi Iain,

How do you do this? Do you have any pictures?
First picture shows the mains filling loop connected ready.(between the 2 red ovals)
Second picture shows filling loop with adaptor that can be used by screwing in the flexi hose on the pressure sprayer into the brass adaptor. This would then take the place of the mains filling loop.



Iain


Title: Re: Solar thermal not circulating
Post by: chris wills on June 16, 2019, 09:28:10 PM
Hi

Quote
Hi Iain,

How do you do this? Do you have any pictures?
First picture shows the mains filling loop connected ready.(between the 2 red ovals)
Second picture shows filling loop with adaptor that can be used by screwing in the flexi hose on the pressure sprayer into the brass adaptor. This would then take the place of the mains filling loop.



Iain

Thanks Iain

  Could I ask for a bit more detail please, even a video if thatís possible?


Title: Re: Solar thermal not circulating
Post by: Iain on June 16, 2019, 09:55:11 PM
Hi
In the top photo the mains connection is at the top. The connection to the solar thermal is at the bottom right. There is a small valve at the mains end. There is a non return valve at the Solar thermal end. The valve at the mains end is opened and the mains pressure then forces water through the flexible loop through the non return valve into the solar thermal loop. It can be charged up to the correct pressure.

If I want to put solar inhibitor in the solar thermal, I just use the other flexi loop  and adaptor to connect the Garden sprayer via the flexible loop to the non return valve into the solar thermal circuit.
The sprayer is pumped up and the fluid goes through the adaptor and the flexible pipe, the non return valve into the solar thermal circuit.

Iain


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 07:47:42 AM
Thanks Iain.
I canít see a non return valve on my system anywhere, could it be on the roof, and do I need one?


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 10:57:52 AM
I am not entirely satisfied that the pump is installed correctly, is it too close to the elbows?
I read that the pump should be fitted away from them.
Is it worth me installing it vertically?



Title: Re: Solar thermal not circulating
Post by: Iain on June 17, 2019, 11:09:20 AM
Hi
I have a non return valve(flap Valve) and an anti thermosyphon loop on mine and they are both next to the cylinder. I fitted my system myself so no idea how yours has been installed. I have also fitted 2 manual air bleed valves, 1 next to the pump and 1 on the return leg in the loft.

Rectangle=anti thermosyphon loop
Oval=non return flap valve and a bypass for it(for when filling the system)
Hexagon=upstand with manual air vent on top
Another upstand and vent is in the loft for the high point air vent.

Iain


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 12:52:56 PM
Hello Iain,

Thankyou for the great feedback, heres an image of mine, can you see anything wrong with the setup?
The pump orientation is not as this picture, but is shown in previous.
When the pump is off the flow pipe (top pipe) is hot, but as soon as the pump kicks in or I manually set it to go the pipe becomes cold.
The pump will run with no problems, but after a while gets very hot with no apparent hot water running through it.
Is there something I can try?
I did consider mounting the pump vertically and removing those awful elbow positions, which could be the cause of it.
In my honest opinion, I don't think it has worked for years, I've been relying on an immersion heater.


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 17, 2019, 01:05:40 PM
You need to take photos of the roof installation so we can see if it has an air bleed on the roof or in the loft. Pump location should be ok. It sounds like it probaby needs a fill and bleed.

Where is the expansion vessel and pressure gauge?


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 04:10:07 PM
I will try to take some roof pictures at the weekend, I don't recall seeing a bleed valve there, what would it look like?

Meanwhile here is the expansion tank and pressure gauge. The upper tank is for my ASHP.


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 17, 2019, 04:31:19 PM
Is there a pressure release valve somewhere and a container to catch the fluid?


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 04:33:33 PM
Yes, the pressure release valve is on the underside of the pressure clock, when this is turned, the fluid will drain to the outside but can be captured in a container of some sort


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 17, 2019, 04:53:12 PM
Is the pressure in the system the same as it was when first fitted?

Most sysetems will also have a flow/ sight tube so you could see if the fluid iS moving.

If it is an air lock and you can't see a bleed valve near the panels or access is hard then I would be tempted to add a bit more fluid to raise the pressure which will 'shrink' the air lock and may allow the fluid to flow. The vent tube at the bottom may well then 'catch' it. You could then let the pressure back down to normal. Be careful how much extra fliud you add though- you don't want the pressure too high.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 05:03:51 PM
As far as I can remember the pressure was at 1 bar when installed and has not dropped or leaked.

A sight tube would be ideal but his has not been installed, is it worth fitting one do you think?

To add more fluid, do you mean just opening the pressure vessel tap or something else, to push it to say 2 bar and then drain it later back to the 1 bar? Does the pump need to be running during this trial?


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 17, 2019, 05:08:15 PM
Use a filling loop or garden sprayer as described before. Re the pump I would pulse it on and off as your filling it. That way you can tell when/if the fluid starts flowing. (You will hear it).


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 05:16:44 PM
I have a manual pump garden sprayer and although you have explained it in detail, I'm still not quite following the method.
You can see my filling points on the image below so in this instance what goes where and is the garden sprayer empty etc etc?


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 17, 2019, 05:41:18 PM
EDIT Fill the sprayer with water and connect to outlet filling connector and pump


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 05:45:05 PM
Fill the sprayer with water and connect to inlet filling connector or outlet and pump

Gotcha.
Another question, when do I stop pumping?


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 17, 2019, 05:47:22 PM
Sorry I think you need to get someone in to do it for you.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 17, 2019, 05:57:01 PM
That's my problem there isn't anyone, nobody want to look a system installed by someone else, so I am left in the lurch so to speak.
Unless you fancy a trip to West Wales to look at it for me?

I'll try the pump on the weekend and see what happens.


Title: Re: Solar thermal not circulating
Post by: TT on June 17, 2019, 09:51:52 PM
http://www.handyantman.co.uk/Navitron%20DIY%20Solar%20Heating%20Review.pdf

Some great advice, from a forum contributor


Title: Re: Solar thermal not circulating
Post by: TT on June 17, 2019, 09:57:31 PM
https://www.navitron.org.uk/forum/index.php?topic=3967.0;wap2



Title: Re: Solar thermal not circulating
Post by: chris wills on June 18, 2019, 07:40:55 AM
Thankyou so much for that document, its well written and provides a clear path to installing a system.

Does anyone know of someone who can call to my home and fix my system, postcode SA16 @South West Wales?

I will try some of the advice I have been given at the weekend but I do believe it needs a bit of TLC from an expert.

I will of course pay for the help, accommodation etc.



Title: Re: Solar thermal not circulating
Post by: TT on June 18, 2019, 07:45:50 AM
https://www.navitron.org.uk/book-a-course/


Best money you will spend probably.
It's the forum host company.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 18, 2019, 08:38:14 AM
Something I would love to do, if I had installed it myself from day 1.
I cant see much being wrong with my system today, I bet if I had an expert on board he could fix it straight away.


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 18, 2019, 09:09:09 AM
I would go back and read this thread again from the start. All the information you should need is contained within it.

Sorry I can't help as I've a broken hand and I'm too busy.


Title: Re: Solar thermal not circulating
Post by: Iain on June 18, 2019, 10:53:42 AM
Hi
I would be tempted to get a proper filling loop connection fitted, Any plumber would be able to do that.
At least you will have an easy method to fill the system. Fill from mains would be ideal if you have a mains supply nearby.
That will allow work to be carried out on the system, checks made and then easy to fill.

An additive can be added later via a garden spray bottle once you are up and running.

You will also need to identify the air vents on the system,

I have put a "T" in my return pipe in the loft. It has a 22mm upstand with a manual air vent on top. Very simple and effective.
Any air settles in the upstand and can then be vented with a radiator key. This is near the high point.
Similar to the one in the picture marked by the hexagon which is the vent by my pump

Iain



Title: Re: Solar thermal not circulating
Post by: chris wills on June 18, 2019, 12:19:17 PM
Thanks Iain,

I did think that as the pressure vessel is connected to the mains that it fills the system when you open?



Title: Re: Solar thermal not circulating
Post by: Tinbum on June 18, 2019, 12:33:02 PM
Yes it should.


Title: Re: Solar thermal not circulating
Post by: Iain on June 18, 2019, 02:19:38 PM
Hi

Quote
Thanks Iain,

I did think that as the pressure vessel is connected to the mains that it fills the system when you open?

Sorry missed that

Iain


Title: Re: Solar thermal not circulating
Post by: chris wills on June 18, 2019, 03:09:13 PM
Hi,

So my plan at the weekend:

1. Check and photograph the panel on the roof, check for bleed valves and open if present until fluid runs out
2. Fill the system up with water from the pressure vessel to about 2 bar, run the pump and look for full circulation

Anything else, I could do, or is this enough to try for now?


Title: Re: Solar thermal not circulating
Post by: TT on June 18, 2019, 04:43:09 PM
Also give the pressure meter a little tap on the face to make sure it hasn't stuck at the same pressure, giving a false reading


Title: Re: Solar thermal not circulating
Post by: chris wills on June 19, 2019, 11:46:29 PM
So latest update, I went onto the roof, you can see the pictures showing each end of the panels.
Spotted an air valve on the return, so i opened it and yes air did bleed until fluid came out, pictures below.
I then added some pressure where I lost a bit, hardy any really, and then I ran the pump manually and noticed that it was in fact cooling the tank down as the roof temp was less than the tank. I would think that when the roof warms up it will have the opposite effect and warm the tank up.....do you think this is logical?

Only the sun will tell............tbc



Title: Re: Solar thermal not circulating
Post by: Tinbum on June 20, 2019, 01:14:00 AM
Yes that sounds great and it's due to be sunny today so possibly a full tank of hot water..

EDIT- you could do with some propper insulation round those pipes.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 20, 2019, 06:57:29 AM
 Fingers crossed.
What grade and type of insulation would you recommend?
Pipe is 15mm.


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 20, 2019, 07:52:54 AM
Fingers crossed.
What grade and type of insulation would you recommend?
Pipe is 15mm.

It's mentioned in the fitting guide refered / linked to earlier.


Title: Re: Solar thermal not circulating
Post by: stannn on June 20, 2019, 09:00:17 AM
Well done Chris. Hereís the pipe insulation which is suited to the high primary temperatures.
https://www.navitron.org.uk/store/solar-panels-hot-water/solar-ancillaries/solar-loop-accessories
Stan


Title: Re: Solar thermal not circulating
Post by: chris wills on June 23, 2019, 11:26:33 AM
Now the weather has warmed up Iím still not getting the heat into the tank.
I went up on the roof earlier and opened the bleed valve with the pump running. I let out air for over 5 mins and still coming out. Is this right? Am I doing something wrong and is this the way to bleed the air?
The pipe on the upper side is really hot but not the n the other. Only hot where the sensor sits showing 100 degrees.


Title: Re: Solar thermal not circulating
Post by: stannn on June 23, 2019, 11:56:46 AM
Yes, all the air must be purged until fluid spits out. 15mm pipe is large for that circuit so more volume for water/air than in a 10mm pipe. Iím assuming that you are re-pressurising with water and not letting pressure fall to zero. Iíve never bled air with the pump running but normally at a cool time.
Stan


Title: Re: Solar thermal not circulating
Post by: chris wills on June 23, 2019, 12:16:50 PM
Ok Iíll give it another go.
Should the pump stay on?
Pressure did not go down too much so I did not refill it


Title: Re: Solar thermal not circulating
Post by: stannn on June 23, 2019, 12:24:25 PM
I would leave the pump off for bleed.
Stan


Title: Re: Solar thermal not circulating
Post by: chris wills on June 23, 2019, 01:11:34 PM
I bled it for about 15 mins. Occasionally water would shoot out. I left it bleed until no air but had no water either at the end. Topped pressure up and now await the sun

edit.
Added more pressure and bled again. Water running freely.
Still waiting for the sun

Edit
Suns out. Pipes cold......damn


Title: Re: Solar thermal not circulating
Post by: chris wills on June 23, 2019, 07:29:47 PM
Is there anyway that the air is being reintroduced into the system.
I honestly thought I had cracked it.


Title: Re: Solar thermal not circulating
Post by: stannn on June 23, 2019, 07:54:08 PM
I suppose that you havenít left any of the valves closed, such as the pump valves?
Stan


Title: Re: Solar thermal not circulating
Post by: chris wills on June 23, 2019, 08:20:08 PM
No pump valves are open


Title: Re: Solar thermal not circulating
Post by: Philip R on June 23, 2019, 08:35:23 PM
Can you confirm that the Expansion vessel diaphragm/ bladder is not punctured.

Philip R
 


Title: Re: Solar thermal not circulating
Post by: chris wills on June 23, 2019, 08:52:31 PM
How do I check this?


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 23, 2019, 09:59:57 PM
Can you hear stagnation (water boiling) in the tubes?


Title: Re: Solar thermal not circulating
Post by: ecogeorge on June 23, 2019, 10:06:42 PM
I bled it for about 15 mins. Occasionally water would shoot out. I left it bleed until no air but had no water either at the end. Topped pressure up and now await the sun

edit.
Added more pressure and bled again. Water running freely.
Still waiting for the sun

Edit
Suns out. Pipes cold......damn
what controller do you have ? Assume the  collector temp is high ? is there a display to show or say the pump is running ? is the pump running ?
george


Title: Re: Solar thermal not circulating
Post by: chris wills on June 24, 2019, 07:53:31 AM
The pump is running fine. I can feel it and have removed the bleed. Itís seems to be spinning  

Canít hear any water boiling. The pipes at Luke at best but the collector temperature goes over 100 degrees easily.

I have a Resol Delta Sol BS controller.

Here is a pic of the controller:


Title: Re: Solar thermal not circulating
Post by: Westie on June 24, 2019, 02:25:35 PM
How do I check this?

Phil is right, you really have to check the accumulator now.   Easiest way is to release the pressure on the loop by opening the bleed or the drain and leave it open, then  pump the bladder in the accumulator up to around 0.5 to 1 bar, leave it 24 hrs and recheck the the pressure has held, if it hasn't the air is leaking out of the bladder into the water loop.   Most accumulators (ie. pressure vessels) have a standard schrader valve at the top , you can use a bycycle pump and a tyre pressure gauge to set/check pressures.
 


Title: Re: Solar thermal not circulating
Post by: chris wills on June 24, 2019, 04:56:31 PM
Yes I will try it next to be sure its OK.
So I drain the complete system? There is an overflow that it release into, maybe some antifreeze left so I will capture it all.
Is it OK with a dry system for 24 hours, I wont damage anything will I?

Here is an image of my expansion vessel, you can see the schrader on top so it should be easy.

I have noticed something, when the immersion heater kicks in (I set it for 16:00 to 03:00 when there is no warm water, so that's all the time!!) I can see a constant drip coming out of the overflow, is this normal.

I don't have any pressure loss at all in the tank.


Title: Re: Solar thermal not circulating
Post by: Westie on June 24, 2019, 05:53:46 PM
Yes I will try it next to be sure its OK.
So I drain the complete system? There is an overflow that it release into, maybe some antifreeze left so I will capture it all.
Is it OK with a dry system for 24 hours, I wont damage anything will I?

Here is an image of my expansion vessel, you can see the schrader on top so it should be easy.

I have noticed something, when the immersion heater kicks in (I set it for 16:00 to 03:00 when there is no warm water, so that's all the time!!) I can see a constant drip coming out of the overflow, is this normal.

I don't have any pressure loss at all in the tank.

,

I would throw a sheet over the tubes to stop them heating up, I would also just open the bleed valve on the collector, some water will get pushed out/lost.

I'm assuming your DHW system is vented with a cold water cistern feeding the hot tank, if the overflow runs that implies hot water is getting pushed back up into the cold water cistern (via the expansion pipe) and raising the water level enough to make the overflow drip.  Try adjusting the ballcock so the cistern stops filling about 40mm below the overflow outlet.





Title: Re: Solar thermal not circulating
Post by: chris wills on June 25, 2019, 08:06:26 AM
I don't have a cistern or tank (excuse my descriptions), the tank just tops up from mains when its low, I'm not sure of the exact way in which it does this and how it is set up, but I do not have a ballcock to move, like a conventional header tank type setup.



Title: Re: Solar thermal not circulating
Post by: Tinbum on June 25, 2019, 08:37:33 AM
From you other posts it looks as if yours is a pressurised system so you won't. The top red tank is the expansion tank.

https://www.navitron.org.uk/forum/index.php?action=dlattach;topic=30618.0;attach=12286;image

It will be the over pressure release valve leaking either through dirt in it , faulty or your system is overpressure. You are superposed to turn the knob on them once in a while for maintenance..



Title: Re: Solar thermal not circulating
Post by: chris wills on June 25, 2019, 01:21:54 PM
I have a small red knob on the end of the pressure gauge, so I guess this is it.

Beginning to think more and more that the pressure vessel is faulty.

Recap - when I bled the panel at 10pm last week of all air (actually just took the cap off and let water out) I was able to manually pump cold water around the system and cooled the tank down.....so....I thought.......when its hot it will warm it up!!!!! It didn't!!

So the vessel may be letting air in to the system again s you guys have said.

I did read that if I pressed the valve down and water came out that the vessel is knackered...is this right?



Title: Re: Solar thermal not circulating
Post by: Fintray on June 25, 2019, 01:28:13 PM
I did read that if I pressed the valve down and water came out that the vessel is knackered...is this right?

If that is the Schrader valve on the expansion vessel you are talking about, then it is knackered.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 25, 2019, 01:33:44 PM
I have yet to do it, but I hope it is, I can replace it then


Title: Re: Solar thermal not circulating
Post by: chris wills on June 25, 2019, 07:34:40 PM
I did press on the air valve and at first a small bit of water came out and then just air, kept it depressed until the gauge read zero. I re-pressureised with water to bring it back to 1 bar and checked again and still just air was releasing.
Do you think its OK or needing further investigation?


Picture of the pressure release valve, is this OK for a solar pressure vessel?


Title: Re: Solar thermal not circulating
Post by: ecogeorge on June 25, 2019, 09:35:07 PM
Please don't be offended  but you obviously are determined to repair this without calling anyone in ...............
Am i  alone in screaming things at the screen ................
Change the pressure vessel -get the same volume in litres marked on it usually. Try screwfix or tool station.
its not guaranteed to fix it but im losing the will to live and its a likely contender.....
George


Title: Re: Solar thermal not circulating
Post by: rogeriko on June 25, 2019, 10:22:24 PM
If you kept the air valve depressed until the water guage read zero you have let all the air out of the expansion vessel!!!   Now you have to start again. Let the WATER out of the system until the guage reads zero and then get a tyre pressure guage and pump air into the air valve until you have 1 bar air pressure in the expansion vessel. Then you can repressurise the water to 1.5 bar and it will work.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 26, 2019, 07:29:12 AM
Please don't be offended  but you obviously are determined to repair this without calling anyone in ...............
Am i  alone in screaming things at the screen ................
Change the pressure vessel -get the same volume in litres marked on it usually. Try screwfix or tool station.
its not guaranteed to fix it but im losing the will to live and its a likely contender.....
George

Hi George,

I am not offended in any way, I welcome all the feedback. My main problem is no-one will look at the system if they didn't install it, so I am left on my own to try and sort it out.
Will get the vessel changed and try this, do you think the drain valve picture I added is OK and should I replace this too?

EDIT: going to buy these and change it all:


Title: Re: Solar thermal not circulating
Post by: chris wills on June 26, 2019, 07:29:51 AM
If you kept the air valve depressed until the water guage read zero you have let all the air out of the expansion vessel!!!   Now you have to start again. Let the WATER out of the system until the guage reads zero and then get a tyre pressure guage and pump air into the air valve until you have 1 bar air pressure in the expansion vessel. Then you can repressurise the water to 1.5 bar and it will work.

I will try this before changing the tank


Title: Re: Solar thermal not circulating
Post by: Iain on June 26, 2019, 04:07:51 PM
Hi
You will probably find the pressure vessel comes pre charged, sometimes to 3 bar which is much too high. Normal rule of thumb is to have the precharge 0.2 bar below system pressure. If you run the system at 1 bar set the precharge to 0.8 bar.

Or if you have 1 bar in the precharge just run the system at 1.2 bar. Just set with a pressure gauge on the shreader valve before you fit.

Iain


Title: Re: Solar thermal not circulating
Post by: chris wills on June 26, 2019, 07:45:09 PM
Hi
You will probably find the pressure vessel comes pre charged, sometimes to 3 bar which is much too high. Normal rule of thumb is to have the precharge 0.2 bar below system pressure. If you run the system at 1 bar set the precharge to 0.8 bar.

Or if you have 1 bar in the precharge just run the system at 1.2 bar. Just set with a pressure gauge on the shredder valve before you fit.

Iain

Great advice one again, it comes pre-charged to 1.5 bar according to the specs, so is that OK to leave as is (I will check with digital pressure gauge first) and then fill the system to 1.3 bar?
Shall I decrease the vessel to 0.8bar and fill the system to 1 bar?


Title: Re: Solar thermal not circulating
Post by: knighty on June 26, 2019, 08:01:56 PM
I've always been told/read pressure vessels should be filled to 80% of system pressure

if you're running 1.5bar water pressure you need 1.2bar of air pressure in it (while there's an open water drain valve)


Title: Re: Solar thermal not circulating
Post by: chris wills on June 26, 2019, 08:22:31 PM
I've always been told/read pressure vessels should be filled to 80% of system pressure

if you're running 1.5bar water pressure you need 1.2bar of air pressure in it (while there's an open water drain valve)

Vessel is pre-charged at 1.5 bar not the water


Title: Re: Solar thermal not circulating
Post by: ecogeorge on June 26, 2019, 09:57:39 PM
Chris -where  in the country are you ??
George


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 26, 2019, 10:41:27 PM


Does anyone know of someone who can call to my home and fix my system, postcode SA16 @South West Wales?




Title: Re: Solar thermal not circulating
Post by: rogeriko on June 26, 2019, 10:49:49 PM
When you get your new pressure vessel take it to a garage and fill it with air to 1 bar. Let some air OUT if it comes precharged to 1.5 bar. Then fit it to your system. This way you cannot go wrong.


Title: Re: Solar thermal not circulating
Post by: greentangerine on June 27, 2019, 12:54:28 AM
I bought a pump filling station a few years back from Toolstation / Screwfix or similar a few years back and it's been a cheap purchase paid back many a time - I stagnate often due to the favourable location I'm in and have leak at about 4 bar up top which depletes the loop fluid.  I have to top up the fluid / pressure about once a month for half the year and the pump station makes it a 30s job.


Title: Re: Solar thermal not circulating
Post by: Iain on June 27, 2019, 06:19:26 AM
Hi greentangerine

Just a quick off topic.
Quote
leak at about 4 bar

Surely even in stagnation you shouldn't reach 4 bar. That is the idea of the expansion vessel. Mine only goes up to 1.5 bar when I tested it in stagnation..
Sounds like your EV is either too small, precharge much too high or lost its precharge or bust bag.
Iain


Title: Re: Solar thermal not circulating
Post by: chris wills on June 27, 2019, 07:32:14 AM
Chris -where  in the country are you ??
George

Hi George, as you may have seen from Iain - SA16 postcode - West Wales


Title: Re: Solar thermal not circulating
Post by: chris wills on June 27, 2019, 02:23:26 PM
I'm back home tomorrow ready for the new trial, think I will do in the evening when its cooler, I want to thank you all for the input and patience, I'm determined to crack this, here's my plan if anyone wants to comment:

1. Drain the system down and switch off the pump and immersion heater
2. Remove the old expansion vessel
3. Check pre-charge pressure of the new vessel and make it to 1 bar
4. Fit new 18L vessel, same as the old one
5. Refill the system with water direct from the vessel fill up to 1.2 bar
6. Bleed the roof air/fill/bleed/fill until no air present and water squirts out the drain valve on the panel
7. Switch it all back on and wait for the sun
8. If it works, drink lots of beer and relax

Anything I have missed guys?


Title: Re: Solar thermal not circulating
Post by: daveluck_uk on June 27, 2019, 02:41:51 PM
Are you 100% certain the rotors are not broken inside the pump? Ie if you circulate the wter with the pump on you should get a fairly strong stream of water coming out of the bleed screw regardless of whether the expansion tank has blown. The pumps would also still hum etc.

Edit. Can you swap it over with you CH pump? Just to rule that out? Just find it strange that the water in the tubes are hot, youvembled its all down but the water still isn't circulating.  I would have thought you'd have got some sort of circulation even if the tank is kaput...


Title: Re: Solar thermal not circulating
Post by: chris wills on June 27, 2019, 03:12:51 PM
Are you 100% certain the rotors are not broken inside the pump? Ie if you circulate the wter with the pump on you should get a fairly strong stream of water coming out of the bleed screw regardless of whether the expansion tank has blown. The pumps would also still hum etc.

Edit. Can you swap it over with you CH pump? Just to rule that out? Just find it strange that the water in the tubes are hot, youvembled its all down but the water still isn't circulating.  I would have thought you'd have got some sort of circulation even if the tank is kaput...

I have removed the bleed screw, not a strong stream of water but the I have put a screwdriver in there and felt it move.
Also, when I bled the air at night from the roof, I was able to send the cool water from the roof around the system and cool the tank. This to me proves the pump is OK. When it all warms up the next day, pump comes on but wont circulate hot water from roof. Thoughts were that after the water expanded in the system, the air was introduced again and back to square one.
I bled again and loads of air again. Fault must be the vessel - at least I hope.


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 27, 2019, 03:29:28 PM
I'm sorry but I just can't see how air is getting into your system  if it is keeping its pressure.

I don't think it's the expansion vessel.

I would repressurise the expansion vessel to the final pressure you want the system at. Fill the system to about 2 bar and with 2 of you- one at the expansion vessel and one on the roof, using mobile phones to keep in contact, bleed the system while keeping the pressure up and the pump running. If its only water it doesn't matter how long your doing it for.

Then let the pressure back down to working pressure.



Title: Re: Solar thermal not circulating
Post by: chris wills on June 27, 2019, 09:17:06 PM
Iíve tried the bleed and fill at night and yes I got the flow of cold water to drop the temp.
However when suns out it does not flow.


Title: Re: Solar thermal not circulating
Post by: desperate on June 27, 2019, 11:57:27 PM
I'm sorry but I just can't see how air is getting into your system  if it is keeping its pressure.

Your EV is knackered you should have air on one side of the diaphragm and water on the other side at equal pressure, there's your air source.
Your pump is air-locked so no flow, do you have an air bleed above the pump to ensure the pump body itself can be purged?



Title: Re: Solar thermal not circulating
Post by: chris wills on June 28, 2019, 03:50:08 AM
Seems consensus is the vessel thatís why I will replace tonight.
Only air bleed on the return going into the cylinder see previous picture posts
The only way I bleed air is to open the screw at front of pump, if itís need an auto vent, please tell me where and what to fit.


Title: Re: Solar thermal not circulating
Post by: Iain on June 28, 2019, 06:42:33 AM
Hi
Quote
.
I'm sorry but I just can't see how air is getting into your system  if it is keeping its pressure.

Totally agree, if there is pressure how can the air keep getting in.

Unless it is not air. Could it be steam from stagnation. With no circulation could be in a state of continual stagnation and the water is just flashing off in the collector.??

Iain


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 28, 2019, 08:54:48 AM


Your EV is knackered you should have air on one side of the diaphragm and water on the other side at equal pressure, there's your air source.



The expansion vessel is there to take up the expansion. Any air in it due to a ruptured membrane would be in the top of the tank and the outlet is at the bottom. The air could initially have got into the system if the tank had been over precharged and was at a much higher pressure than the water and ruptured. After bleeding that air out I wouldn't expect it to get more air in though as the system is holding pressure and has been de-pressured during the bleeding process. . The tank hasn't been mentioned as leaking water or anything. The tank could easily be tested rater than just replaced.


Title: Re: Solar thermal not circulating
Post by: chris wills on June 28, 2019, 01:53:45 PM
So I drained all down. Put a bar into the bladder. Filled the system do 1.2.and waited.

Same old situation.

Bled the panel and I donít think itís air itís steam. And goes for a long time. Over 15 mins.

I have the vessel. Is it worth changing. Probably not.

I get it all to work when roof is cold. I can cool the water by manually switching pump on. As soon as itís hot trouble starts.

Pump is really hot though. As usual


Title: Re: Solar thermal not circulating
Post by: Iain on June 28, 2019, 03:14:27 PM
Hi
I would be very tempted to check your pump again. It can rotate but not pump. Impellers can break or become loose on the shaft.

Is it possible to take it out and hold the inlet of the pump in a bucket of water and test it does actually pump? Carefully hold it with the inlet in the water but don't drop it!!!,
My pump will force air and water around the system providing there is actually water in the pump at the time.

Iain.


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 28, 2019, 04:03:01 PM
So I drained all down. Put a bar into the bladder. Filled the system do 1.2.and waited.

Same old situation.

Bled the panel and I donít think itís air itís steam. And goes for a long time. Over 15 mins.

I have the vessel. Is it worth changing. Probably not.

I get it all to work when roof is cold. I can cool the water by manually switching pump on. As soon as itís hot trouble starts.

Pump is really hot though. As usual

Did you bleed it on the roof when refilling it?

When bleeding when it is in stagnation it will continue to vent.

Have a look at below link and you will see why and the principles.

http://aee-intec.at/0uploads/dateien48.pdf



Title: Re: Solar thermal not circulating
Post by: desperate on June 28, 2019, 07:21:51 PM


Your EV is knackered you should have air on one side of the diaphragm and water on the other side at equal pressure, there's your air source.



The expansion vessel is there to take up the expansion. Any air in it due to a ruptured membrane would be in the top of the tank and the outlet is at the bottom. The air could initially have got into the system if the tank had been over precharged and was at a much higher pressure than the water and ruptured. After bleeding that air out I wouldn't expect it to get more air in though as the system is holding pressure and has been de-pressured during the bleeding process. . The tank hasn't been mentioned as leaking water or anything. The tank could easily be tested rater than just replaced.


I take your point, but it is possible for air from the dry side of the diaphragm to enter the system if it is perforated. Didn't Chris say he saw some water come out of the schraeder valve?? Take a look at a new EV with a precharge on the dry side the diaphragm is hard up against the outlet, so depending on the relative pressures between the dry and wet side given a bit of a leak air can get forced out of the "bottom" of the EV.

It only takes a small amount of air to lock the pump and then once the system over heats you can get a vast volume of steam from it. I have seen this scenario many times and I think it fits the symptoms Chris reports.

Whaddya think?

Desp


Title: Re: Solar thermal not circulating
Post by: biff on June 28, 2019, 09:51:14 PM
Sounds good Desp,
                       Good tee see yee  back in the fold. :crossed
                                      Biff


Title: Re: Solar thermal not circulating
Post by: rogeriko on June 28, 2019, 09:52:53 PM
You cannot use the screw on the end of the pump to get the air out, that will never work.


Title: Re: Solar thermal not circulating
Post by: rogeriko on June 28, 2019, 10:03:01 PM
You need to get a proper filling pump and you connect it to the 2 blue taps in your photos. Close one of the pump taps and let the filling pump fill and purge the system properly. It takes about 2 minutes.


Title: Re: Solar thermal not circulating
Post by: rogeriko on June 28, 2019, 10:07:11 PM
Time to buy a couple of pints for your local plumber. I have 3 of these but I live hundreds of miles away. You can even fill the system at midday when it is boiling with this. the pump pressure is too much for the air or steam so it blows it around the system and out into the container. You could make one yourself if you had a normal pressure pump.


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 28, 2019, 10:09:05 PM
He said:
'I did press on the air valve and at first a small bit of water came out and then just air, kept it depressed until the gauge read zero. I re-pressureised with water to bring it back to 1 bar and checked again and still just air was releasing.'

Not sure about the first bit of water as the valve is at the top but sounds to me as though it's fine.


Title: Re: Solar thermal not circulating
Post by: rogeriko on June 28, 2019, 10:14:08 PM
You will NEVER be able to fill the system because the air is up in the pipes on the roof and your little circulating pump will NEVER be able to push the air down to the air vent at the bottom. the only way to fill your system is to get up on the roof at night and crack open the pipes on both ends of the collector and then pressurise the system and while it is STILL pressurising go back up on the roof and close the pipe connections when there is no more air coming out. make sure the pump is off when you do this. Expect to use tons of water to make sure the ar is all out of both flow and return.


Title: Re: Solar thermal not circulating
Post by: Iain on June 28, 2019, 10:18:53 PM
Hi
Quote
.
You will NEVER be able to fill the system because the air is up in the pipes on the roof and your little circulating pump will NEVER be able to push the air down to the air vent at the bottom. the only way to fill your system is to get up on the roof at night and crack open the pipes on both ends of the collector and then pressurise the system and while it is STILL pressurising go back up on the roof and close the pipe connections when there is no more air coming out. make sure the pump is off when you do this. Expect to use tons of water to make sure the ar is all out of both flow and return.
But he has an air vent on the roof.
So should be easily possible
Iain


Title: Re: Solar thermal not circulating
Post by: rogeriko on June 28, 2019, 10:46:11 PM
It might have gotten hot and blocked up. best to remove it and use the hole to purge the air and then reinstall a new one. One little bubble of air in the pipework will stop the pump, and I mean little bubble.


Title: Re: Solar thermal not circulating
Post by: rogeriko on June 28, 2019, 11:27:44 PM
Dont forget to include the tap so air cannot get back in afterwards. That is when the liquid cools and shrinks it will pull air in through the vent. The tap must be closed after comissioning.


Title: Re: Solar thermal not circulating
Post by: Pile-o-stone on June 29, 2019, 07:26:40 AM
Is the best option not to just rip out the overly complex solar thermal setup and just replace it with a much simpler solar PV and immersion heater diverter setup? Fit and forget?

You then get hot water and electricity and none of the overly complex piping issues (and no problems with freezing pipes, stagnation and loss of potential energy when the tank is full of hot water and the solar stops working).

I understand the attraction of owning and maintaining antique and obsolete cars, but energy generation systems?


Title: Re: Solar thermal not circulating
Post by: Iain on June 29, 2019, 07:41:52 AM
Hi

Is the best option not to just rip out the overly complex solar thermal setup and just replace it with a much simpler solar PV and immersion heater diverter setup? Fit and forget?

You then get hot water and electricity and none of the overly complex piping issues (and no problems with freezing pipes, stagnation and loss of potential energy when the tank is full of hot water and the solar stops working).

I understand the attraction of owning and maintaining antique and obsolete cars, but energy generation systems?

If you have limited roof area solar thermal is good. And you do not get stagnation if designed correctly and with my Powervault even continues working during a power cut.
My own 2kw PV is ideal size for my Powervault battery and household needs and my Solar thermal looks after my hot water faultlessly for over 10 years. If I replaced my solar thermal (which gives out over 2kw )I would only be able to add 720w worth of PV in its place.
So for some households solar thermal is cost effective and very efficient. The downside of using PV for heating water, why use high grade energy just for heating water. What a waste.
Iain


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 29, 2019, 08:49:39 AM
You will NEVER be able to fill the system because the air is up in the pipes on the roof and your little circulating pump will NEVER be able to push the air down to the air vent at the bottom. the only way to fill your system is to get up on the roof at night and crack open the pipes on both ends of the collector and then pressurise the system and while it is STILL pressurising go back up on the roof and close the pipe connections when there is no more air coming out. make sure the pump is off when you do this. Expect to use tons of water to make sure the ar is all out of both flow and return.

Not true at all. I've done it many times and so have many others. He has the vent on the roof and has used it.

It might have gotten hot and blocked up. best to remove it and use the hole to purge the air and then reinstall a new one. One little bubble of air in the pipework will stop the pump, and I mean little bubble.

His vent on the roof is fine .


Title: Re: Solar thermal not circulating
Post by: desperate on June 29, 2019, 09:57:25 PM
Sounds good Desp,
                       Good tee see yee  back in the fold. :crossed
                                      Biff

Cheers Biff, it's good to be here.

Desp


Title: Re: Solar thermal not circulating
Post by: desperate on June 29, 2019, 10:08:49 PM
He said:
'I did press on the air valve and at first a small bit of water came out and then just air, kept it depressed until the gauge read zero. I re-pressureised with water to bring it back to 1 bar and checked again and still just air was releasing.'

Not sure about the first bit of water as the valve is at the top but sounds to me as though it's fine.


Hmm maybe, but as you know EVs are charged at the factory with dry Nitrogen and unless someone has recharged it with a bicycle pump with water in it, it's hard to see where that water has come from. Also Chris has mentioned that when the immersion is on, water drips from an over flow, that's a sure sign that an EV has lost its charge or is too small to accomodate the expansion. Although it is not clear which over flow Chris is refering to, also quite why the immersion would affect the solar loop is a bit confusing, through the heat EX maybe?.

I think the next thing you need to do chris is really prove the EV, can you take it out of the system and pump it up with a tyre pump and monitor it for a day or two? Then as you say it would be worth mounting your pump on a vertical pipe run and have it pumping uphill, that will make sure it is self bleeding. Do that and I would bet your problem will be history.

Best of luck.

Desp


Title: Re: Solar thermal not circulating
Post by: desperate on June 29, 2019, 10:14:55 PM
You will NEVER be able to fill the system because the air is up in the pipes on the roof and your little circulating pump will NEVER be able to push the air down to the air vent at the bottom. the only way to fill your system is to get up on the roof at night and crack open the pipes on both ends of the collector and then pressurise the system and while it is STILL pressurising go back up on the roof and close the pipe connections when there is no more air coming out. make sure the pump is off when you do this. Expect to use tons of water to make sure the ar is all out of both flow and return.


Most standard CH pumps are capable of lifting water up to 50 feet, providing they do not have air in them, so it should be possible to pulse the pump and clear the air in the upper reaches of the pipework. A pump similar to the one you show or even a pump up garden sprayer would make the operation a whole lot easier though.

Desp


Title: Re: Solar thermal not circulating
Post by: Tinbum on June 29, 2019, 10:45:41 PM
Also Chris has mentioned that when the immersion is on, water drips from an over flow, that's a sure sign that an EV has lost its charge or is too small to accomodate the expansion. Although it is not clear which over flow Chris is refering to, also quite why the immersion would affect the solar loop is a bit confusing, through the heat EX maybe?.


Desp

Pretty certain that is the DHW cylinder one.


Title: Re: Solar thermal not circulating
Post by: chris wills on July 01, 2019, 08:32:57 PM
Time to buy a couple of pints for your local plumber. I have 3 of these but I live hundreds of miles away. You can even fill the system at midday when it is boiling with this. the pump pressure is too much for the air or steam so it blows it around the system and out into the container. You could make one yourself if you had a normal pressure pump.

Update and hopefully the final one............

I asked a local plumber to take a quick look, he suspected the pump immediately and removed it to test, he said it was all fine. He also said there was nothing wrong with the expansion vessel, he gave it a few taps, tested the schrader then that was it.
He had a long think and before putting the pump back on he asked which way round it went, luckily I had a picture to show him. He reckoned it was the wrong way round, so we tried it......all perfect, flow came through and in 5 mins was hot, I know have it all working perfectly.
When I changed the pump over, I copied the direction of the original one which did not work, or so I thought.

Thanks to everyone for there for help on this, its much appreciated.


Title: Re: Solar thermal not circulating
Post by: stannn on July 01, 2019, 09:22:07 PM
TFFT. Weíll all heave a collective sigh of relief Chris.
Stan


Title: Re: Solar thermal not circulating
Post by: biff on July 01, 2019, 09:28:57 PM
Stann an wan.
        I was just gonna say that very thing.
 exhappy:
      Biff.


Title: Re: Solar thermal not circulating
Post by: stannn on July 01, 2019, 10:03:54 PM
During this saga, my own solar system sprouted a leak, at the screwdriver slot of a pump-isolating ball-valve. Thatís not repairable. I replaced them with unions with gate valves after a plumber said they are more reliable.
Stan


Title: Re: Solar thermal not circulating
Post by: ecogeorge on July 01, 2019, 10:40:08 PM
TFFT. Weíll all heave a collective sigh of relief Chris.
Stan


Hooray  ............at last .......... well done .


Title: Re: Solar thermal not circulating
Post by: donegal on July 02, 2019, 12:53:34 AM
Chris,

You are now 'the expert' on your own system, i admire your perseverance and it will pay off if you have a solar problem again

Tony


Title: Re: Solar thermal not circulating
Post by: todthedog on July 02, 2019, 06:04:26 AM
Hurrah, well done Chris.
What will we all discuss now! :hysteria

An epic tale of perseverance.


Title: Re: Solar thermal not circulating
Post by: Tinbum on July 02, 2019, 09:25:17 AM
I'm really surprised as I looked at the pump in the first page of the thread and it looked correct. I would expect the hot water from the roof to go into the top of the coil in the tank.  ??? ???

Is the temp sensor on the panels on the wrong end?


Title: Re: Solar thermal not circulating
Post by: chris wills on July 02, 2019, 09:45:16 AM
I'm really surprised as I looked at the pump in the first page of the thread and it looked correct. I would expect the hot water from the roof to go into the top of the coil in the tank.  ??? ???

Is the temp sensor on the panels on the wrong end?

What I now see is the temp being sensible and not in the 100's, maybe that is the case with the temp sensor, but I'm not touching anything for now.
At the end of the day, I'm getting hot water for free.
Thanks for the message though, maybe one day I will look at it lol......


Title: Re: Solar thermal not circulating
Post by: Tinbum on July 02, 2019, 09:57:24 AM
When we were discussing the mounting location of the pump at the very beginning I did look at the way the flow was going through the pump and it was correct.

The system has probably either not worked at all right from installation, unless the pump had been installed the wrong way round and then when you changed it you actual put it in the correct way.  :laugh:

The flow and return have probably got crossed on the way up to the roof.



Title: Re: Solar thermal not circulating
Post by: chris wills on July 02, 2019, 11:17:41 AM
I only have water in the system for now but have been advised to change it for glycol ASAP.
Can anyone recommend a good brand and typically how much I would need. I can then get it pumped in.


Title: Re: Solar thermal not circulating
Post by: TT on July 02, 2019, 01:41:14 PM
Fill with water, enure no leaks.
Drain down contents into buckets to measure capacity
Add 40% glycol mix


Title: Re: Solar thermal not circulating
Post by: Countrypaul on July 02, 2019, 02:33:44 PM
Since Navitron sell solar kit, they should be your first port of call I would have thought.


Title: Re: Solar thermal not circulating
Post by: rogeriko on July 02, 2019, 11:52:45 PM
My question is.......A solar thermal system is Bidirectional.   The panels can be connected either way round, so can the coil in the tank, so why?????? ?????    stir: stir:


Title: Re: Solar thermal not circulating
Post by: Nickel2 on July 03, 2019, 07:39:39 AM
Purchase flow-marking tape and stick it all over everything for future reference?

(https://i.postimg.cc/w1TZ0Qkn/flow-marking-tape.jpg) (https://postimg.cc/w1TZ0Qkn)


Title: Re: Solar thermal not circulating
Post by: Tinbum on July 03, 2019, 07:50:18 AM
My question is.......A solar thermal system is Bidirectional.   The panels can be connected either way round, so can the coil in the tank, so why?????? ?????    stir: stir:

And I thought you had fitted loads of these. banghead:


Title: Re: Solar thermal not circulating
Post by: Westie on July 03, 2019, 09:12:01 AM
My question is.......A solar thermal system is Bidirectional.   The panels can be connected either way round, so can the coil in the tank, so why?????? ?????    stir: stir:

Haha...  good point.  He could have reversed the check valve or the pump.  Although, best practice is to install all the control stuff like pump, check valve, bleed etc.. on the cooler return to the collector.

I think we should award Chris a prize for perseverance - well done.  Actually maybe we should all have one  whistle

 


Title: Re: Solar thermal not circulating
Post by: Westie on July 03, 2019, 09:16:03 AM
Purchase flow-marking tape and stick it all over everything for future reference?

(https://i.postimg.cc/w1TZ0Qkn/flow-marking-tape.jpg) (https://postimg.cc/w1TZ0Qkn)


Maybe a simpler system is to always check that the arrow on the check valve and the arrow on the pump always point the same way  ;D


Title: Re: Solar thermal not circulating
Post by: stannn on July 03, 2019, 09:23:51 AM
Can you buy tape with arrows pointing the other way?
Stan


Title: Re: Solar thermal not circulating
Post by: Countrypaul on July 03, 2019, 09:51:36 AM
Can you buy tape with arrows pointing the other way?
Stan

I bet its more expensive  :hysteria


Title: Re: Solar thermal not circulating
Post by: biff on July 03, 2019, 11:55:35 AM
 ;D I have rolls n rolls of it Stann.
  They are in the bottom side up box.
           Biff


Title: Re: Solar thermal not circulating
Post by: Nickel2 on July 03, 2019, 04:27:38 PM
They don't cost any more, you just open the box at the other end, or open it sideways as required:
(https://i.postimg.cc/wR3xCtJV/Up-or-down-arrows.jpg) (https://postimg.cc/wR3xCtJV)


Title: Re: Solar thermal not circulating
Post by: chris wills on July 03, 2019, 10:11:53 PM
OH Noooooooooo

Today roof temperature got really hot, about 135 degrees and for some reason its now affected the flow again.
Could it be that I need to replace the water with glycol?

I jumper up on the roof and bled again, just in case but water shot out.

I have again in the system stagnated water, why the heck has this happened?

Is it a setting on the controller maybe?

For the last few days I have been having lots of hot water


Title: Re: Solar thermal not circulating
Post by: rogeriko on July 03, 2019, 10:32:39 PM
Whats the upper temperature setting on the controller, how hot is the max temp on the water tank sensor. If it is set low it will turn off the pump when it reaches that temp.


Title: Re: Solar thermal not circulating
Post by: rogeriko on July 03, 2019, 10:40:33 PM
Glycol properties


Title: Re: Solar thermal not circulating
Post by: chris wills on July 03, 2019, 11:29:56 PM
Whats the upper temperature setting on the controller, how hot is the max temp on the water tank sensor. If it is set low it will turn off the pump when it reaches that temp.

Just checked.
Collector temp was set to 140, I have upped it to 160 degrees C.
Tank temp was 60 so changed to 65 degrees C

This maybe the issue as the tank was filling up at 59, may have tipped over the 60 mark at some point.
Could be a drain and fill in the morning

lets see!

Edit update.
No joy. Roof is far too hot at 125 degrees. When it was working it was at 80.

Edit 2.
Drained down. Refilled. Now back to ok. Letís see what happens with new settings too

Edit 3
Changed solar cylinder Max to 90. Itís now 76 on roof. Tank has 70 in it. Result ok.


Title: Re: Solar thermal not circulating
Post by: chris wills on July 18, 2019, 09:47:43 PM
Just an update...........all good....... :D

Next step...........add some glycol to complete


Title: Re: Solar thermal not circulating
Post by: pj on July 19, 2019, 12:41:01 PM
My question is.......A solar thermal system is Bidirectional.   The panels can be connected either way round, so can the coil in the tank, so why?????? ?????    stir: stir:
The manifold on my system only has a pocket for the temperature sensor on one end, so although it could be plumbed either way, it only works properly if the flow is in the correct direction.