reddal Posted October 10, 2017 Share Posted October 10, 2017 Hi, Recently my GSHP has been playing up again - occasionally not heating water and displaying an error "High pressure plant fault". This goes away when you hit escape and it then seems to get on with the job. I asked the contractors that service it to come check it. They looked at the filters but couldn't see anything much. They recommended that the UFH side of the system should be cleaned out and an extra filter should be fitted between the heating system and the heat exchanger. They implied it was probably a good idea to do this regardless as the system is 5 years old now. Their estimate for this work is : Back-flush heat exchanger – 2 men for 6 hrs £498.00 Fit filter and add chemical – 2 men for 2 hrs £241.00 Flush after 2wks and dose – 2 men for a day £664.00 All those figures ex-vat - and only an estimate. I think they want 2 men because one guy knows about the GSHP and the other is a UFH specialist. This company is the only one locally that has anyone that knows anything about GSHP - so I don't get to shop around. Its been working fine the last few days - so I'm wondering if the problem is fixed anyway... A few questions : Is it a good idea to get this done every 5 years anyway? Is it likely to fix my problem (if I still have one)? Is the estimate reasonable? thanks as ever for any advice - reddal Link to comment Share on other sites More sharing options...
Ian Posted October 10, 2017 Share Posted October 10, 2017 (edited) I can't really comment on the UFH issues but I've just had a normal central heating system power flushed - 2 plumbers for 1 full working day cost £300 + Vat. Edited October 10, 2017 by Ian 2 Link to comment Share on other sites More sharing options...
Ferdinand Posted October 10, 2017 Share Posted October 10, 2017 1 hour ago, Ian said: I can't really comment on the UFH issues but I've just had a normal central heating system power flushed - 2 plumbers for 1 full working day cost £300 + Vat. Good price. Last time I was thinking about poweflushing a very small house it would be 400-600, and it was less than 1k to replace all the pipes and rads so I did that instead. Link to comment Share on other sites More sharing options...
jack Posted October 10, 2017 Share Posted October 10, 2017 No idea on 1 and 3, but re: 2, do they really need to have two high-rate people there at all times for all jobs? Seems like overkill to me. I especially think that an UFH specialist is pointless. The UFH circuits are trivially easy to understand and could easily be handled by the GSHP specialist. And what is the UFH specialist doing for the 6 hours it will apparently take to flush the heat exchanger? Link to comment Share on other sites More sharing options...
ProDave Posted October 10, 2017 Share Posted October 10, 2017 Are you sure that error is right? I wired a self installed GSHP in a new build and when fired up for the first time gave this sort of error. When I contacted technical help for the heat pump. it turned out the issue was the wter in the ground loops was not circulating due to the poor way he had plumbed it and inability to bleed an air lock. Are you sure the fault does not relate to poor ground water flow? Link to comment Share on other sites More sharing options...
reddal Posted October 10, 2017 Author Share Posted October 10, 2017 1 minute ago, ProDave said: Are you sure the fault does not relate to poor ground water flow? No - not sure. The documentation is not helpful on this point. The GSHP guy checked the brine loop side and didn't see a problem - so is assuming it must be on the other side - particularly because he was surprised not to find a filter between the heating and the heat exchanger - and thinks that should be fixed (and system flushed) regardless. If he is right - and this is something that needs to be done as part of routine maintenance every 5 years or so then I guess I have to get it done. Its quite expensive though so I'm tempted to just leave it... Link to comment Share on other sites More sharing options...
PeterW Posted October 10, 2017 Share Posted October 10, 2017 If it needs a filter then just add a Magnaflow or similar and a gauze filter. You can get cheap ones from BES and they are half an hour to fit as it’s not at any sort of pressure really. Link to comment Share on other sites More sharing options...
jack Posted October 10, 2017 Share Posted October 10, 2017 Worth a call to the GSHP manufacturer to see whether they have any thoughts? I found Panasonic's tech department very helpful when I had a couple of odd errors during installation. Link to comment Share on other sites More sharing options...
Nickfromwales Posted October 10, 2017 Share Posted October 10, 2017 Where's the contamination coming from that warrants the filter ? What metal components are there in the wet circuit ? I think these two are handing you your ass on a plate TBH, not just on the rates but with a guesstimate of what's ACTUALLY wrong. Even with a low dilution of inhibitor 5 years is crazy for someone to suggest it's contaminated imo. And £1000+ every 5 years? You'd have been better off on LPG The rates aren't crazy for what they are but 2 guys to fit a bloody filter ? Close the isolations and chop the pipe, in with the filter, purge and away to go. Hour for one guy max. You can dose it yourself with a hozelock bottle. Are you up for tackling any of this yourself ? We can advise through pics etc. 1 Link to comment Share on other sites More sharing options...
reddal Posted October 10, 2017 Author Share Posted October 10, 2017 5 minutes ago, Nickfromwales said: Where's the contamination coming from that warrants the filter ? What metal components are there in the wet circuit ? There are some pipes, pumps, manifolds etc. Nothing unusual I don't think. 6 minutes ago, Nickfromwales said: Even with a low dilution of inhibitor 5 years is crazy for someone to suggest it's contaminated imo. And £1000+ every 5 years? You'd have been better off on LPG Tell me about it... I was sold on GSHP because it was supposedly very cheap to run/maintain. This will be the 3rd time in 5 years I've had a £1000+ bill to try to make it work properly, with plenty of smaller costs along the way. If it was a boring oil or gas boiler I could choose from a dozen engineers to work on the system. With a GSHP in the system I'm a bit stuck. 6 minutes ago, Nickfromwales said: Are you up for tackling any of this yourself ? We can advise through pics etc. I fear it would be beyond me - plumbing isn't something I have any skills in - and if I muck it up I would end up having to go back to the same people to put it right - and the bill for that would be much worse! Thanks for all your help. I think I will wait and see if the problem re-occurs (I half suspect they fixed the problem by cleaning the filter on the brine loop). - reddal Link to comment Share on other sites More sharing options...
ProDave Posted October 10, 2017 Share Posted October 10, 2017 I would want a more positive diagnosis of what this fault means. In the case I mentioned, it was because the ground loop was not circulating, so the heat pump was trying to extract heat from a neat exchanger with no flow through it, and that causes something to overheat and over pressurise. Ir it is a blockage and hence low flow in the secondary I would expect if you monitored the flow and return temperature, you would find the flow temperature way too hot if crud was impeding flow. Does this happen? All basic checks you would expect them to do before just diagnose by "try it and see" (at the customers expense) 1 Link to comment Share on other sites More sharing options...
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