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Renewable Energy: Ground source heat pump problems

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  1.  
    • CommentAuthormikejd
    • CommentTimeDec 26th 2007
     
    This is a continuation of a previous post - 'Ground Source Heat Pump Question' - as I am still experiencing problems which the so-called 'accredited installer' can't seem to solve.

    The system was installed and commissioned in November, worked for about 10 days albeit at a very low temperature which was the subject of the previous post. It hasn't worked since except for short periods as various 'solutions' were tried to get it working. When it stopped after about 10 days working the heat pump showed an 'Error level 2' fault. There were two suggestions to sort this - one to turn off and back on, the second was to clean the strainer. Both allowed the pump to start working again but in both cases only for less than 24 hours.

    The next suggestion was to provide a larger ground loop pump. This was installed, the system started and shut down 'Error level 2' after about 9 hours. Next the ground loop was repressurised as the pressure has dropped - same result. The latest suggestion is that there is insufficient antifreeze allowing formation of ice crystals and slowing the flow. They have calculated that 79 litres of antifreeze is required; they supplied 75 litres with the system which has already been put in. The MD of the company, who I am now dealing with, has now gone on Xmas holiday until 14 Jan so I assume there will be nothing happening until then.

    There has been a suggestion that the problem lies with the ground loop borehole which may not be fully grouted. If so the solution would have to be sorted with the borehole contractor, letting the 'installer' off the hook. At the moment I can't think of any way to check the grouting of the borehole, short of excavating and redrilling.

    The 'installer' appears reluctant to actually come to site to try and investigate although I have now written to them to say that this is what I think they should do. I am also considering trying to find an independent engineer who could check the system, although this would obviously cost me more money. So far I have not named the 'installer' but I may do this soon if I get no satisfactory solution and I will certainly not be recommending them to anyone else.

    I would be interested in any comments/advice anyone can offer.

    Mike Davies
  2.  
    I have no experience with GSHP's but I note you have put in all antifreeze supplied, So my question is, is the antifreeze already diluted (i.e. 4:1) as straight glycol is very viscus and hard to pump as well as has lower heat transfer properties then water!

    My solar antifreeze has only about 25% glycol and is good to -25 degC (off the top of my head) so my logic tells me a higher dilution for GSHP is possible.

    Not sure if it helps but may need further investigation.
    • CommentAuthormikejd
    • CommentTimeDec 26th 2007
     
    The antifreeze was diluted 1:1 with water and then pumped into the ground loop which was already full of water. The antifreeze content is supposed to be about 30%, the total volume of the loop is estimated to be about 250 litres.
    • CommentAuthorroughbert
    • CommentTimeDec 27th 2007
     
    I hate it when people who know nothing post answers to my technical problems. But this won't stop me from asking the obvious questions:

    1) If the loop was already full how could you add more.
    2) if there is ice how do you know it has melted before adding antifreeze

    sounds like you have a leak!
    • CommentAuthorCWatters
    • CommentTimeDec 27th 2007
     
    I've zero experience with GSHP but....

    > There has been a suggestion that the problem lies with the ground loop borehole which
    > may not be fully grouted. If so the solution would have to be sorted with the borehole
    > contractor, letting the 'installer' off the hook. At the moment I can't think of any way to
    > check the grouting of the borehole, short of excavating and redrilling.

    Presumably the bore hole can be pressure tested on it's own to test the sealing?
    • CommentAuthorCWatters
    • CommentTimeDec 27th 2007
     
    I hate to suggest this but I think it would be worth having a brief chat with your solicitor or CAB. It might sound too soon and I'm not suggesting you immediatly take the installer to court! Rather you should perhaps check to ensure _you_ are taking the right steps to ensure compliance with any consumer protection legislation. For example you might have a legal right to reject the installation as unsatisfactory but only if you take action within x days/months or write a carefully worded letter. If the installer recommended the bore hole company perhaps the installer has some joint liability? That's the sort of thing the they can help with at this stage.
  7.  
    Hi Mike,

    What make and model of GSHP do you have?

    Paul
    • CommentAuthormikejd
    • CommentTimeDec 28th 2007
     
    roughbert :
    1. the other end of the loop was open allowing the water to be displaced.
    2. the antifreeze was added before the heat pump was commissioned and started up. The formation of ice crystals in the loop due to insufficient antifreeze is a suggestion by the 'installer' and not actually known.

    CWatters :
    the ground loop in the borehole was pressure tested after installation and before connection to the heat pump. This, however, would not show whether the borehole surrounding the pipes had been fully grouted, only the integrity of the actual pipes.

    I note your comments wrt solicitor/CAB and have been thinking that I need to get some independent advice. The 'installer' is accredited with the Energy Saving Trust and I would like to take it up with them but as I have an application in to them for a grant (possibly £4k) I am hesitating about contacting them as it would probably compromise the approval of the grant. The borehole contractor was not one recommended by the 'installer', their suggested contractor proved difficult to get a quotation from and I ended up getting one from another drilling contractor (who I would regard as being a reputable company).

    Paul @ Carbon Free :
    the heat pump is a Terra S/W GA Compact 7kw from ID Energie Systeme

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