[Christian]

Hi Folks,

we're having a 'glass half full' problem with our ground source heat pump.
Our GSHP has been installed at the end of last year by an excellent renewable energy company from Duns (Borders). Because it's an old, rather big farm house, we needed to dig out 6 trenches * 75m for the heat collectors. Each of the trenches holds one loop, brine going up on one side and back again on the other side (still with me?). Our field for the trenches is on the hill side with the highest point for each of the 6 trenches about 20m above the manifold (that's where all the 6 loops come together and the feed is going back into the house).

Now, when it was installed end of last year, we reallized that the brine wasn't running through all 6 loops - indeed, only one or two of them had circulating brine and the house got cold. Installer guessed that it was due to an air lock at the top of the loop and tried to flush it out using bigger and bigger pumps. He then installed a bigger heat pump and now it looks like maybe 4 or 5 of the loops are operating.

So - the heating is great and with the bigger pump it's been running without problems (mind you, it's summer....). We've ordered an (environmentally sound) solution for our heating, and we got one (glass half full). Alternatively, we've ordered a system that collects heat from 6 loops - and we didn't get one.

How would you look at that? Will the missing loop cost us once it gets nasty nasty out there?
https://www.accidentalsmallholder.net/forum/Smileys/default/thinking.gif

Cheers

Christian
(desperate smallholder)

P.S. PM me if you need recommendation for the installer or metric conversion)

[cloddopper]

Did the installer do a flow meter check on the pipes with plain water in them to see what the flow was through each individual loop before commissioning the system ? Just incase one loop has been partly crushed & is restricting the flow of water ?
 Does each loop have a pressure gauge on either end so you can readily se any problems & which loop it is in?

I suspect it should also have flushed out any air if the volume of water being used was enough .
 Does each loop have shut off cocks  at both ends of each of the loop pipe ?

[landroverroy]

Hi Folks,



P.S. PM me if you need recommendation for the installer or metric conversion)

Thanks for the offer, but it doesn't seem much of a recommendation when he's still only got possibly 4 of your 6 loops working.    Methinks I would not be wanting to use an installer that first of all leaves you with only half the system working, and then on being called back still only achieves about 66%. [size=78%] [/size]

[Christian]

Hi Cloddopper,
As far as I have understood, the system was flow meter checked and OK'ed before commissioning. All loops have pressure gauges (just checked), but only on the flow back into the manifold. It actually looks as if right now only one loop got any pressure on it - thanks for pointing this out to me! And yes, there are shut off cocks on both ends - can those be shut to force the brine through each of the loops one at a time?

Hm, Landroveroy - you're probably right, but I think I give him the benefit of a doubt (it's usually me who gets things worng). But he needs to get it sorted.....

Thanks for advice!

[cloddopper]

I'm not a heating engineer but I am a retired electro / mechanical engineer ,what I said previously just seemed the be things I'd need to check .

 I think I'd be seeking  expert advice and legal advice as something seems very wrong .


 I got ripped off for £ 18,600 for a conservatory , internal double glazed doors out into it & a new roof line & guttering for the garage because I didn't do my home work & I didn't know a but the greater power of being able to recover things by the sheriffs  sorting out warrants for the high court .

I take it is under warrantee by him being a registered installer ? or am I being optimistic in both cases ? Who installed the water loops & back filled the trenches ?


 Check with trading standards , citizens advice bureau and the county court help desk to find out how get a decision of liability & compensation given in your favour .
I'd give him so many days to put it right.

If he fails …. no excuses seek trading standards help . 

Inform him of the following in writing , pop it in a chocolate box size parcel and  pay to have him or his family to sign for the package from the royal mail .( proof of delivery )

A lot of shysters are well versed in not signing for recorded delivery letters & ignoring the postman's  post card telling them there is a letter to be signed for at the local sorting office etc . The chocolate box delivery usually catches  a lot out  .

If it's not done by the specified time then  I'd look to see if I could  get someone to do it and chase him for the costs via the county court backed by the sheriffs courts as they are far more powerful than a county court judgement trying to be collected by a bailiff  . 

If your in Scotland it might be different .

[chrismahon]

It should be no different than a central heating system where, to remove air locks, you simply shut off all the radiators but the one that isn't working which concentrates the flow through it. Isn't there a bleed valve at the top of each loop as well?

[honeyend]

We and a neighbour have air source , and our friend have under floor with a pellet boiler, plus they are fully off grid for electric. The common theme with all of these is that the experts are not really experts. They have been on a course, read the book, fitted a few and then when they do anything which is not standard and get a problem they haven't got a clue.
  All of us have had problems, which gone on for months. My husband is on first name terms with the technical bod from Panasonic, we are on our third plumber, they just do not take the advice given even when they are sent diagrams, they do not really understand how it works so they adapt what they have always done. I have now decided my husband actually knows more but lacks the confidence to do the work himself. We had a bad batch of valves and he now changes them himself.
  The bottom line its not what you paid for, work out what is not working, get a quote to get it sorted from someone else and give them a deadline, and depending on the amount go to small claims.
 

[Womble]

All loops have pressure gauges (just checked), but only on the flow back into the manifold. It actually looks as if right now only one loop got any pressure on it - thanks for pointing this out to me! And yes, there are shut off cocks on both ends - can those be shut to force the brine through each of the loops one at a time?

I'm trying to understand what you mean here Christian. Can you describe the equipment on each loop?  For example, is it:


Inlet manifold => Inlet valve => Loop => Pressure gauge => Outlet valve => Outlet manifold?

[Christian]

Hi folks,
Oh dear, lots of unhappy builders out there - this is an excellent wake-up call!

Womble, I'm trying to attach a diagram that shows the set up in the manifold - hope it makes sense. ChrisMahon, I was wondering about bleeding valves on the top of the loops, as well. There are none and I'd hate to have them dug up again - but maybe that's the best solution. Honeyend - can you lend us your husband?
 
Cheers,

Christian
(desperate Smallholders)

[pgkevet]

I have no idea if it would help here but I did hear about an old trick of adding washing-up liquid to rad systems to shift an air-lock on the theory that the foaming breaks it up???

[Womble]

OK, I'm not a heating expert, but I am a process engineer, and this is what I'd try.


The gauges are in a funny position really, since they're all going to read more or less the same regardless of what's going on in the loops (because they're all reading the pressure of the return manifold more or less, and not the individual loops).


I'd try closing all the valves and then opening up only one loop at a time, so that all of the flow is directed through a single loop. That then tells you something - do you get the same pressure reading for each loop, or are some different? If one pressure is lower than the rest for instance, that suggests a restriction in the pipe - either a pinch or kink somewhere, or an air lock. Perhaps having all the pressure directed to a single loop might be enough to clear any bubbles though.

Maybe try that and report back? 

[cloddopper]

I'd try and  put the pressure gauges on the other side of the shut off valves by udoing the gauge , putting in a sealing plug with ptfe tape round it . Only doing one at a time so you don't get confused as to what goes where or where it came from .

Then inserting a "Tee " union adaptation that can take the repositioned pressure gauge on the other side of the shut off's . ( again use PTFE tape to make the seal if it needs it ) .   

That way a single individual loop can be checked , tested or isolated and the pressure reading in the loop found & recorded .

If that can be done then it's a case of isolating all but one loop call it No 1  label it  start the pump and run it for 10 min to bring out any dissolve/absorbed air and actual air bubbles in the system .  Then work your way through the other loops , again labelling them .


 Roughly how long is each loop , are there any joints in the buried pipe work ( often problematic ) ? What was used in the back filling of the trnches  , any rubble big boulders or sharp rocks in it .

Do you know if the pipes were rolled out in the trenches or just pulled off the coil ?the latter tends to instill twists in the pipe . Do you know if the pipe was flat in the trench when it was back filled or loads of wavy in the air lengths of pipe?


I've just been thinking that the pipes ought to have been blinded with at least 300 mm of sharp sand over them to soften the pressure out & ensure no sharp stuff is close to them that might sever /puncture the pipe if the is ground heave /movement  .
 But I cannot find any specific suggestions or recommendations as to the initial covering .
The use of  sand might even also act as a moisture sleeve to allow better thermal transfer into the pipe

[Christian]

Amazing folks,
thank you so much! Clodopper & Womble - you are stars!

I am a bit hesitant to start doing something to the system - it might backfire when dealing with the heating installer (there's a warranty to worry about). But I do feed your suggestions straight to him and demand action (or reasons, why this can't be done). Clodopper, the ground here is light clay all the way down to the core of the earth with few round sandstones in it - whatever we dug out went straight back. Each loop is 75m up the hill - 900m in total (donno, is that much?). Pipes were loaded onto a spining Jenny before laying them into the ground with no joints and few bends, so they should be free running....
I'll have the installer test them one by one the way you & Womble suggest - I'll keep you in the loop....

Thanks again

Christian