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Author Topic: Seem to be over the main problems, but still not right..........  (Read 11705 times)
rogermunns
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« Reply #15 on: December 31, 2010, 09:31:38 AM »

I've tried bleeding at the pump using the large screw that you undo if you want to turn the shaft. Am I letting air in?

UFH pump in HeatPump assembly is 2,0metres below bottom (feed in) manifold.

First photo shows the 8-way manifold in kitchen corner cupboard. There are 7 loops and one spare. I have coupled inlet and outlet of the spare, but kept those valves closed. Inlet is bottom, you can see the adjustable flowmeter displays. They're cr*p. Also you will note that the pipes going into the floor have coloured sleeves round them. Red and blue. You will see that the colours do not correspond to the main valve colours on the right. That's because, when I bought the manifold, the valve heads were on the wrong way round. A call to the supplier eco-hometec revealed that the flowmeters are on the inlet. So I swapped over the blue and red valve heads.

I'm only making a point of this because it's typical of the hassle and duff info that I've had concerning the manifolds and everything else to do with the installation of the UFH pipework.

Second photo is of a spare manifold, identical to the installed one except 6-way instead of 8-way. I got two manifolds because I needed about 800metres of pipework and that meant buying two complete kits. Two loops; 500m with 8-way manifold and 300m with 6-way manifold, two pumps.

On this second photo you can see inlet at bottom right (still with blue valve handle!) and each leg with a valve / flowmeter. Top leg has electro-actuated valves (some are fitted). In my installation I have no electro-actuators installed, I don't believe in room thermostats when the response time is hours. The intention was just to adjust the flow valve thingys as I need to.

The valve / flowmeters are really awkward to operate, especially being inside a cupboard. And I've only ever seen one of them indicating flow. They are poor IMHO. 


* R0015965gimp.JPG (90.14 KB, 400x300 - viewed 256 times.)

* R0015969gimp.JPG (81.17 KB, 400x300 - viewed 289 times.)
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titan
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« Reply #16 on: December 31, 2010, 09:59:03 AM »



Top leg has electro-actuated valves (some are fitted). In my installation I have no electro-actuators installed,

Just a comment, in my system  the  the actuators open the valve so with no actuator heads fitted there would be no flow unless the screw caps are fitted.
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Alan
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« Reply #17 on: December 31, 2010, 10:28:49 AM »

On mine if the plastic cap is not fitted the valve is open.

If the actuator is fitted and not powered the valve is shut.

Regards

Alan
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rogermunns
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« Reply #18 on: December 31, 2010, 10:30:51 AM »

Same with mine Alan. Right stupid arrangement.
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knighty
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« Reply #19 on: December 31, 2010, 11:43:31 AM »

you need to check the pump is full of water.... it won't do anything at all if it's full or air (or half full)

if it is full or water, you could try turning it around, so see if the water would flow in the opposite direction ? (worth a shot)


other than that, you'll either have to keep pushing it through with your hose pipe, or fit a bigger pump to try and force it through...... bigger pump idea might be best..... then you could just leave it turned off once everything is running and the water should circulate through it ok ?

something like this should hit 80psi and 40l/min (a lot of people use these for bio diesel, and that's what they get).... as long as that's not going to knock any of your fittings off ?

do you have any kind of header tank in the system ? (I''m assuming not) - so you will need to sort out somewhere for the air to go while you push it through.... even if you just split your return pipe and put it in a bucket of water temporarily..... you need somewhere for the air to escape of you'll never be free of it
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Iain
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« Reply #20 on: December 31, 2010, 11:47:29 AM »

Hi
Could a auto air vent on the output of the pump sort out the air problem? At least ensuring the pump is kept free of air to allow it to pump.
Iain
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welshboy
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« Reply #21 on: December 31, 2010, 12:19:59 PM »

The pump on mine is a Grundfos 25-120-  this is a bit about them.

UPS 25-120 circulators are designed to cater for the majority of domestic wet central heating systems up to 35kW. UPS 25-120 has an energy saving 3 speed motor and can accommodate larger domestic systems and higher resistance microbore pipework.

The UPS 25-120 is a high head domestic circulator and normally requires a 1" BSP Union Set.
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welshboy
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« Reply #22 on: December 31, 2010, 12:29:24 PM »

This is a very old post link but maybe worth checking out as yours is an old machine

http://www.navitron.org.uk/forum/index.php/topic,572.msg3566.html#msg3566
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Mostie
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« Reply #23 on: December 31, 2010, 01:53:10 PM »

Hmm.... is that auto air bleeders I see on the manifolds? Could the return one be pulling air in? Is the manifold the highest point of the system?
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rogeriko
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« Reply #24 on: December 31, 2010, 02:08:52 PM »

getting air out of any system is difficult at best, opening the screw on the pump is not enough because you need a strong FULL PIPE flow to clear the air especially down hill. You have to close the taps one by one and undo each pipe from the return manifold and drain it into a bucket 20 to 30 litres each pipe. It has to drain fast with pressure to remove the air bubbles. Close the air release valve on the return manifold because the pump can suck air in there.
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rogermunns
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« Reply #25 on: December 31, 2010, 02:56:35 PM »

You won't believe it, but at last it's right!

Bleeding bleeding! Main problem turned out to be those stupid flow valves which have a twin thread - I was only opening one).

Now, after 30 minutes or so running the system I have UFH water out of pump at 23deg. C (when I had flow probs this reached 48deg. C in 3 minutes or so before compressor tripped). UFH water return is at 16deg. C.

One thing, though  --  after switching on to go on to green light, UFH pump starts at once, another relayclicks in at about 40 seconds, but then it is several (7 or Cool minutes before compressor comes on. Is this normal?

I still think I am down on flow, I'll crawl into the cupboard again and see whether I can twist any of the flow valves some more.   

One last thing a question about pressure rise of UFH water as the temperature goes up. Will the big red pancake expension thingy take it up? Remember, it is 6 years old. Should I charge it? How? Bike pump with pressure gauge?

Just  made it before the new decade begins!! Thanks again to all who have helped.
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rogermunns
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« Reply #26 on: December 31, 2010, 03:28:18 PM »

Thanks to those who spoke of air and bleeding etc. I will look into more auto bleeders.

The manifold is not at the highest point. The system is pretty normal - 7 loops in ground floor, screeded over 7cm. But because we have concrete stairs (between 3 and 4 tonnes) I took one of the loops up to first floor attached onto the underside of the concrete stairs then back down again. At the top of the stairs I have access to this pipe - and I deliberately cut and fitted a tee at the top, valved so I could bleed any air that collected there. That complete loop is the least important of the house and could be locked out if necessary. That loop has been reassuring, 'cos I can directly feel the temperature rather than having to wait until the concrete floor warms up.

I am monitoring floor temperature above one of the loops (thermocouple taped to floor and covered with insulation). T = 15,8 deg. C. at the moment.
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titan
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« Reply #27 on: December 31, 2010, 04:09:08 PM »

I sounds like you only have a vent on one loop (from 7) not having the manifold ( with flow and return autovents)  at the highest point  means air  may continue to cause  a problem. I have a similar set up to you with the  utilities in a basement, I would have liked the manifold down there also but  in the end decided it was too much of a risk of continual air entrapment problems. It is not a problem in a conventional radiator set up but UFH loops are prone to air problems if they are not purged with decent flow rates during commissioning and have permanent  effective autoventing in use. 
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rogermunns
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« Reply #28 on: December 31, 2010, 05:21:08 PM »

Thank you Titan.  I will carefully watch what is happening  and, more probably-than-not, fit more autovents. I may also try to re-route the main pipes coming up from below, although that will be very difficult.
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rogermunns
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« Reply #29 on: January 01, 2011, 10:43:59 AM »

Happy New Year to all members!

It's now run for 2 hours today, 4,5 hours yesterday with nothing to note except some icing up on pipes from the HP side.

Is this dangerous to the compressor / exchanger? How much icing up before switching off? Is there an autoshut-off for this situation?

Floor temperature has increased from 13,0 to 19,7 deg. C.

Well water temperature coming in has fallen from 12,5 to 10,7 deg. C.   Water returning to well temperature fallen from 7,4 to 4,5 deg. C.

I estimate amount of water in well is 6 cubic metres. Overnight temperature recovery of well water was from 10,9 to 11,4 deg. C. Given time, this would presumably recover back to 12+ deg. C.
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