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Author Topic: new to the world of Solar Thermal  (Read 4552 times)
neilglos
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« on: April 19, 2016, 12:01:12 PM »

Hello, new to the world of Solar Thermal, I have just installed the Navitron designed and sized system - 30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close. South facing in North Gloucestershire.

I have a few questions -
1.   Programme settings on the controller - is it best to leave settings @ default, eg sensor temps, recooling off etc?
2.   Should I change the pump speed on my Grundfos UPM3?
3.   Are there any procedures to take during holidays, cover tubes with a Tarp, change the controller settings to holiday mode?
4.   How often should I replace the Antifreeze?
5.   During the last week mid-April, I have managed to collect a full tank of ~50 degree water, will I have problems with overheating in the summer?
6.   I installed the solar loop and tubes myself with my dad, is it possible to get my system checked and signed off to claim the RHI?
Thanks Neil
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30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close
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« Reply #1 on: April 19, 2016, 12:59:42 PM »

Hello, new to the world of Solar Thermal, I have just installed the Navitron designed and sized system - 30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close. South facing in North Gloucestershire.

I have a few questions -
1.   Programme settings on the controller - is it best to leave settings @ default, eg sensor temps, recooling off etc? 
The only setting that might take some consideration is the cut out temperature, particularly with an unvented cylinder  you probably have to limit the temperature.   
2.   Should I change the pump speed on my Grundfos UPM3?
Generally you should use a variable speed setting on the controller and a medium or high setting on the pump. That allows slow steady transfer of heat in low light conditions.

3.   Are there any procedures to take during holidays, cover tubes with a Tarp, change the controller settings to holiday mode?
That is a tricky one.  Generally covering tubes is an invitation to burglars  so not very advisable  but leaving the controller to cut out circulation puts a lot of strain on the plumbing. For holidays  a simple way to dump some DHW water into  a  garden tub or  to use  some other heat  dump, to central heating, for example, is  desirable.

4.   How often should I replace the Antifreeze?
It should last at least ten years.

5.   During the last week mid-April, I have managed to collect a full tank of ~50 degree water, will I have problems with overheating in the summer?
Probably not if you are using water constantly.  Heat gain drops off rapidly with rising water temperature.

6.   I installed the solar loop and tubes myself with my dad, is it possible to get my system checked and signed off to claim the RHI?
Worth a try at least but most support systems depend on prior application.   

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DHW 250 litre cylinder  60 X 47mm tubes
Heating  180,000 litre straw insulated seasonal store, 90X58mm tubes + 7 sqm flat collectors, 1 kW VAWT, 3 kW heatpump plus Walltherm gasifying stove
9fingers
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« Reply #2 on: April 20, 2016, 08:29:13 AM »

I have installed a similar system to your 30 x58mm tubes on 49 degree south facing roof but I have a 357litre store.
I have found the need to install a heat dump even though my store runs at up to 93 degrees (as close to boiling as I feel comfortable with)

Unless you are drawing off fair amounts of DHW during the day, your system will likely stagnate on a regular basis and that is not good practise in my book and will gradually cook your inhibitor if nothing else.

Search on this forum for details of the ANTMAN Dump which is a very elegant dumping scheme and when implemented will mean you can go away on holiday leaving the system looking after itself safely.

hth

Bob
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neilglos
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« Reply #3 on: April 20, 2016, 09:32:36 AM »

Thanks for the replies, as ever I have a few more questions.
7. How will I know my system is stagnating?
8. I like the idea of a heat dump for peace of mind;

8.1 D.24 in my controller manual looks like a good fit, Solar + cooling 2

What pump would you recommend from Navitron?
What size radiator would be recommended?
Should in install in a bathroom?
or externally @ the back of my house in the shade?

8.2 D.25  in my controller manual also looks like I can loose heat through my CH, Solar + cooling 3
I assume my Worcester Bosch boiler pump switches on and opens both values? how would I get a switched live? is this a good option vs a dedicated heat dump?

The CH options looks like the easiest option, just a cabling job....

thanks Neil
« Last Edit: April 20, 2016, 11:23:08 AM by neilglos » Logged

30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close
9fingers
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« Reply #4 on: April 20, 2016, 11:42:29 AM »

When it stagnates, the rooftop temperature rises dramatically and the top manifold fills with superheated steam pushing the HTF down into the pipework.
Pressure gauge usually goes up and it may blow off into the expansion vessel.
The elevated temperature compromises the buffer solution balance in the HTF which gradually turns acidic and in extremis, eats through the copper pipes.
Although HTF inhibitor should last a good few years, I would check the pH as part of an annual service to check it is still slightly alkaline or neutral. When pH drops below 7 then it is an early warning to drain and refill the system when convenient - usually in the winter when you don't have to manage the draining of hot HTF

If you use the Antman dump system you don't need extra radiators or pump.
I have mine rigged to go through the bathroom radiator and towel rail which has the bonus of nice dry warm towels even in summer as my dump operates on most sunny summer days. NB you might not get as regular dumping as my surplus dregs of PV also goes into the store
You need some relays as well as cabling but yes it is an electrical only solution so no plumbing.
If you have thermostatic radiator valves, remember to open at least one fully during the summer period when the dump might be required.

hth

Bob
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neilglos
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« Reply #5 on: April 20, 2016, 01:22:11 PM »

thanks Bob, last question I think.

I plan to use the Solar S-Plan+ HD to CH 2RS Nav (BTW only have one heating zone) unless I have missed something,
is it the case to stop the boiler turning on the flame, pump on and just opening the valves circulating the water, I manual set the temperature to say 30 (in the summer only) as my Worcester only has a Switched Live?

** update, I think, I have figured it out, I remove the live from the boiler to the pump and divert it via the relay C1, Switched live triggers the flame....**

Neil
« Last Edit: April 20, 2016, 02:10:24 PM by neilglos » Logged

30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close
9fingers
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« Reply #6 on: April 20, 2016, 02:55:06 PM »

thanks Bob, last question I think.

I plan to use the Solar S-Plan+ HD to CH 2RS Nav (BTW only have one heating zone) unless I have missed something,
is it the case to stop the boiler turning on the flame, pump on and just opening the valves circulating the water, I manual set the temperature to say 30 (in the summer only) as my Worcester only has a Switched Live?

** update, I think, I have figured it out, I remove the live from the boiler to the pump and divert it via the relay C1, Switched live triggers the flame....**

Neil

Basically yes. My WB has a single switch to live as a demand for heat. I put a normally close relay contact in series with that. I have a pair of changeover contacts for the pump. Moving contacts to pump, NC contacts to boiler pump control and NO contacts to fused mains. Another NO contact is in parallel with the room stat. All the relay coils are driven by the dump output from the TDC.
Leave  boiler controls alone. You can even switch the boiler off in the summer months.

I'm using no gas for DHW between about mid March to mid-late October.
As I type the store is sitting at 82-83 top to bottom giving me a capacity of around 300 litres of DHW at 50 degrees.

A photo of my calorimeter display taken some time ago.



Top row = cyl temps on 7 sensors top (left) to bottom (right)
2nd row actual temp of cold inlet to mixer and mixer output - both drift towards ambient over time
3rd row long term average minimum (trough hold) for the cold inlet, followed by long term average Maximum (peak hold) at the mixer output.
bottom row No of mS since last estimate, no of litres that can be drawn before thermostatic mixer goes out of regulation (calculated from the above)
software version (home brew) single digit down counter in seconds to indicate activity. This should never stop as the watch dog will kick in and reboot it.

In the fullness of time, this volume of available water will be used to decide as and when to fire the boiler. I just have to incorporate a real time clock into the software and way of storing the DHW demand profile I want.

hth
Bob

PS Before anyone asks, I'm not going to publish my software mainly because I don't consider that it meets any acceptable standard and has been hacked together with minimal documentation.
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neilglos
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« Reply #7 on: April 21, 2016, 09:18:32 PM »

Hi Bob, relay arrived today, I have connected it up without power to the coil to check normal function, it all works.... BUT my boiler reports a H09 error communication problem with the pump, do you have the same error or problem, i have taped/isolated up the original live from th boiler and connected the pump to pin 9 (my boiler in a 24i greenstar only a few month old), may need to concider a different method new pump and rad. cheers Neil
« Last Edit: April 21, 2016, 09:54:14 PM by neilglos » Logged

30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close
9fingers
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« Reply #8 on: April 21, 2016, 09:54:05 PM »

Hi Bob, relay arrived today, I have connected it up without power to the coil to check normal function, it all works.... BUT my boiler reports a H09 error communication problem with the pump, do you have the same error or problem, i have taped/isolated up the original live from th boiler and connected the pump to pin 9 (my boiler in a 24i greenstar only a few month old) cheers Neil

Your boiler must be cleverer than mine which does not check for the presence of the pump motor. It does not have a display for error messages. Nice and simple (and dumb!)
Does your H09 error go away by itself when the pump is reconnected or do you have to reset it manually? if the latter which would be a PITA, then wire a low power filament light bulb or maybe a spare relay coil direct to the boiler pump terminals to give it something to chew on.

hth

Bob

PS late afternoon yesterday my dump came on. So even in April, my 30 tubes had taken the store to 93degrees and 101 degrees on the roof when I looked at the controller
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neilglos
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« Reply #9 on: April 21, 2016, 10:07:38 PM »

The error did not disappear....I also could have done with the dump yesterday, ran the bath quickly....back to the drawing board, I think, I will go for a separate pump and rad a little more research needed, TBH not sure I fancy voiding my warranty. thanks for ur help!!
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30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close
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« Reply #10 on: April 21, 2016, 10:15:27 PM »

Try using the relay to cut the power to the whole boiler when dumping - that should remove the H09 problem.

Otherwise a second pump in parallel with the boiler one would still  let you use your current rads as the dump.

Lots of way of skinning this cat!

Bob
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Antman
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« Reply #11 on: April 22, 2016, 08:59:30 AM »

Hi Neil
The schematics are only meant for Regular boilers with external pumps (not combis and some system boilers create issues with access to the pump wiring integral with the boiler). Searching the WB website I assume you may have the Greenstar i 24kW system boiler which seems to have the digital display and a whole lot more complicated control system electronics.
If so then your only option would be to use a separate pump.

It is worth noting that there are a few regular boilers that use triac/SSR switching in the pump neutral. These would not work with my published schematics either.
The option to overcome this is to use the spare pole 4 of the relay to isolate the pump neutral:
 PumpN from boiler to NC4
 PumpN to C4
 Neutral feed to NO4

This completely isolates the pump from boiler in HD mode.

I am sure someone on the forum has used the older generation Greenstar Ri OK.

Regards
Antman
« Last Edit: April 22, 2016, 09:35:21 AM by Antman » Logged

20 x 47mm, 172 l cylinder, Heat Dump, 15 x Sanyo HIT-H250E, SB4000TL,  Nestor Martin IQ13 WBS
DIY Solar System Support at http://www.handyantman.co.uk/antman.html
All support is voluntary and free of charge. I'm not employed by Navitron so responses may not be same-day
Iain
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« Reply #12 on: April 22, 2016, 09:26:45 AM »

Hi
My old boiler used the Antman(similar) system and worked well in dumping the heat. I fitted a new boiler and as it is more sophisticated and had a warranty I decided to keep the dump separate.
All I did was to fit a CH pump/ circulator in series with a zone valve. These connected between one leg of the cylinder boiler coil circuit and one leg of the CH circuit.
The dump signal opens the zone valve,which effectively links the CH circuit and the HW cylinder coil circuit, when this opens, the micro switch on the zone valve switches on the pump. The water goes around the boiler coil in the cylinder,removes the heat and sends it around the CH circuit. Works very effectively.
I also added a relay to the circuit that inhibits the boiler just in case it is told to run at the same time.
No mods to the boiler, so warranty OK, works in a similar way to the Antman system and very simple and effective.

Iain
« Last Edit: April 22, 2016, 09:30:49 AM by Iain » Logged

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20 x 65mm Thermal and 180ltr unvented
Powervault 4Kw - G200 Lithium-Ion (LiFePO4)
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neilglos
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« Reply #13 on: April 22, 2016, 09:33:10 AM »

thanks for the update, it is a system boiler - Greenstar i System (24), I do suspect the boiler continually monitors the pump :-( as i have no error when I restore the default wiring.

I was researching last night and my system is sized correctly eg 30 tubes 250l tank ie within 7.5l per tube;
There are two camps here, dump or no dump?
I have set the tank max temp to 75 as I have a TMV and shall monitor, worst case I cover the tubes for holidays...
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30 TUBE 58MM ALU. LOW PROFILE PANEL, Single Line pump station with Grundfos UPM3 HE pump, MTDC CONTROLLER, 255L TWIN COIL UNVENTED STAINLESS STEEL & Spirovent 3/4" H with auto close
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« Reply #14 on: April 22, 2016, 09:36:47 AM »

Sorry, I found the info on the WB site and was updating my original post as you typed.
Antman
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20 x 47mm, 172 l cylinder, Heat Dump, 15 x Sanyo HIT-H250E, SB4000TL,  Nestor Martin IQ13 WBS
DIY Solar System Support at http://www.handyantman.co.uk/antman.html
All support is voluntary and free of charge. I'm not employed by Navitron so responses may not be same-day
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