@transparent West Oxfordshire

Mike

Try making contact with the Eynsham-based group who are a member of the Transition Towns Network.
They state that they have an 'Energy Working Group', so are likely to know the good installers in the area.

A post-script to my recent issues now that the weather is unseasonably warm after being so cold. Daily kWh usage is down to 1/4 of what it was 2 days ago and calm has returned to the Patrick household.

The plumber visited, replaced a faulty pressure gauge (on the heating expansion vessel) and relief valve, installed a more convenient filler loop and eliminated the air from the system. His bill £288. Which is why I try to use them only for fixing obvious faults and not for chasing down the elusive inefficiences from which I think my installation still suffers.

Result of plumbers visit was that bathroom towel rails now work again, the near constant sound of trickling water has gone and for 48 hrs at least the pressure gauage was registering about 1.5 bar. But it is now back to Zero. (I'm not chasing that down again, for now)

It is good to fix these things but I'm sure the improvement in kWh usage is down to the weather.

It continues to be helpful to participate in this forum. But I have to remind myself that the volume of issues raised is an indication of how far the industry needs to go before domestic heat pump installations are as routinely consumer friendly as conventional gas boiler ones. I haven't checked but I suspect there are few people getting online to discuss their gas central heating. As things stand I fear there will be a tsunami of unhappy customers if anything like the government's 600,000 installations per year target is met before the problems many of us here have experienced are resolved.

Mike

Posted by: @mike-patrick

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I haven't checked but I suspect there are few people getting online to discuss their gas central heating.

I don't share your suspicion because I saw plenty of complaints in other energy-saving forums and local social network groups last week about inefficient oversize gas boilers actually spiking to something like half their 28kW rating while trying to keep typically-underinsulated British homes warm. They're just spread out across more sites because anyone complaining about a heat pump in those groups just gets ridiculed for getting a heat pump when the Daily Mail or whoever says they can't work in the UK.

Posted by: @mike-patrick

↑

A post-script to my recent issues now that the weather is unseasonably warm after being so cold. Daily kWh usage is down to 1/4 of what it was 2 days ago and calm has returned to the Patrick household.

The plumber visited, replaced a faulty pressure gauge (on the heating expansion vessel) and relief valve, installed a more convenient filler loop and eliminated the air from the system. His bill £288. Which is why I try to use them only for fixing obvious faults and not for chasing down the elusive inefficiences from which I think my installation still suffers.

Result of plumbers visit was that bathroom towel rails now work again, the near constant sound of trickling water has gone and for 48 hrs at least the pressure gauage was registering about 1.5 bar. But it is now back to Zero. (I'm not chasing that down again, for now)

It is good to fix these things but I'm sure the improvement in kWh usage is down to the weather.

It continues to be helpful to participate in this forum. But I have to remind myself that the volume of issues raised is an indication of how far the industry needs to go before domestic heat pump installations are as routinely consumer friendly as conventional gas boiler ones. I haven't checked but I suspect there are few people getting online to discuss their gas central heating. As things stand I fear there will be a tsunami of unhappy customers if anything like the government's 600,000 installations per year target is met before the problems many of us here have experienced are resolved.

Mike

If the pressure has dropped to zero then I suspect that you have a leak somewhere.

Posted by: @mike-patrick

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As things stand I fear there will be a tsunami of unhappy customers if anything like the government's 600,000 installations per year target is met before the problems many of us here have experienced are resolved.

We might have to upgrade our hosting servers when we’re at 600,000 installs per year 🥲

I agree with @mjr. I’ve seen a lot of online chatter (and received a few emails) about gas and oil boilers, and their respective inefficiencies and running costs. For the first time, efficiency matters in all heating systems. To this point, the running costs of gas and oil boilers were ‘minimal’ so homeowners didn’t care about inefficient installations. Now that they’re expensive to run, people care, and they’ll be looking at ways to improve the efficiencies of their heating systems, which is a good thing.

@mjr 

Posted by: @mjr

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about inefficient oversize gas boilers actually spiking to something like half their 28kW rating while trying to keep typically-underinsulated British homes warm

Ah yes, the 25kW boiler they installed in my 100 m2 home when the daily average power never exceeded 3kW during this recent cold snap.  I don't think this "condensing" boiler ever did much condensing until I turned down the outlet temperature they set it at.  The burner can't turn down far enough to permit continuous operation anyway.

@derek-m I've been away over New Year and as I always do on returning home, took a look in the heating cupboard to see if all is well, or not, with our heating system.

Belatedly I believe I have discovered the source of the leak which causes the pressure drop.  Attached photo shows the 50L expansion tank with brown stain emerging from pin-prick sized hole around the welded central joint in the vessel. The tank needs replacing. From what I've now looked up online the brown stain is from rusting inside. I don't understand why they arise but gather this type of hole is characteristic of expansion tank failures.

The label on the tank says its a Zilmet, manufactured in 2014. My system was installed in 2016 so I wonder what it was doing in the intervening 2 years. Perhaps it was just kicking around at our installer's depot and they thought, "oh we'll use that one, it's been here a while".

Given the blue glycol stain under the vessel as well it would be pertinent to ask, "Mike, why didn't you (or the plumber who was here 10 days ago) spot this before, it's in plain sight?"

My own excuse is that much of the floor of the heating equipment cupbord is stained with glycol from a bigger leak in another part of the system a couple of years back. It isn't obviously wet and the pin-prick leak I've found is very slow. As for the plumber, this is fairly typical of my experience. They seem to be incapable of looking beyond what they have been told to fix and taking a wider view on their own initiative. It's in stark contrast to the local garage who service my 12 year old Golf. I take it in for a service, they find what's wrong, tell me and then fix it. This is a plumber on Grant's approved list and I would expect them to have some sort of holistic understanding of overall ASHP installations and not just of the pump itself.

From the Zilmet price list this looks like £150 for the part , plus another call out charge for the plumber. Never a dull moment!

@derek-m

I don't think the photo attached properly to my last post. Here it is

Mike

Latest update on the leaking buffer tank.......

The one used on my system has been discontinued. Grant now use a volumiser/LLH which sits outside, next to the ASHP on the same stands, between it and the wall of the house.

This is an altogether more expensive piece of equipment and a lot more work to install.

But, we have found a supplier in the Irish Republic that still has in stock the old volumiser like mine which is basically a canister with an inlet  and an outlet. It's relatively straightforward to swap it for the leaking one.

Unfortunately the supplier won't ship to England (thank you Brexit). I'm now looking at travelling on the ferry from Fishguard to Rosslare to collect it in person (this gives new meaning to the term, "Click and Collect"). All in, this is still a cheaper and technically simpler solution than any available alternative. Our heating engineer has suggested we could probably get away with no tank at all - taking out the old one and directly connecting the inlet and outlet pipes. But I'll play safe and not make any changes to the installation that could cause new problems.

Perhaps I should buy two tanks in Ireland so I have a further spare should I still be living the nightmare in another 6 years when the new replacement has also worn out!

Mike

A cylinder should last more than 6 years. It could have had a manufacturing fault, but the picture seems to suggest it corroded from the inside out. Begs the question, has your system adequate concentration of corrosion inhibitor and a magnetic filter unit?

Also, if it has flow through it and is a buffer tank, should it not be insulated? Unless it's located in a space you want to heat?

@allyfish Good point.

Judging by how hot to the touch it is sometimes I suspect the tank is not insulated. The replacement will be a smaller (30L) insulated one.

Yes and no doubt when the old tank is removed we'll find a lot of loose corroded material in there which has also travelled around the pipework.

Mike