The new ASHP + underfloor heating system has been fairly successful since we moved in, in April, but has failed its first real test since then.
After a very mild month so far, on Sunday the outside temperatures dropped markedly. Not a freeze up, but I was very keen to see where the power consumption was going. At 8pm on Monday, it switched itself off with an error code "U2". I discovered this at about 11pm, reset the system and restarted it. It errored again 20 minutes later and shut down. Code means "high compressor discharge temperature" which apparently would be consistent with it being low on R32 refrigerant. Game over until its been fixed. Injuneer coming tomorrow.
Meanwhile, it's been a test for our disaster recovery plan, the one we didn't have. First job was to sort out hot water. I had to work out how to get control of the immersion heater which is managed by the system that has shut itself off. Turns out there is a more or less hidden setting which allows it to heat the water according to its usual program but using the direct heater, so that is now sorted.
Next the space heating. I hadn't even tried out the multifuel stove we fitted, but it was all signed off and ready to go once I had bought some logs, log pliers, poker, etc. Fired it up yesterday afternoon. We ran it until bedtime at the setting for its nominal 5kW output. I'm very happy with it - by bedtime the room stat was reading 24.5C, with the sitting room doors wide open to allow heat into the rest of the house. The kitchen/living room got up to 23C, all the bedrooms (doors open) were showing 20+. The stats are at face height and tend to read about 2 degrees higher than the temp experienced when sitting down, but the temperatures achieved were near-normal for us (and hotter in the sitting room where the stove is).
Only the bathrooms feel chilly, and in fact are at about 16-18C. We used a couple of fan heaters for an hour this morning which worked well.
The ASHP is under guarantee for 5 years and will I hope be fixed tomorrow. All the refrigerant is in the outside unit so there'll be no tearing into walls and ceilings to find the leak, assuming there is one.
I also ordered a new gadget that has just arrived. A heat-powered stove top fan.
smile.amazon.co.uk/gp/product/B077VG3759
I've been told these work well enough to be useful but I had no idea how they operated. It has an electric motor that I under stand is supplied by a Peltier semiconductor device, which is, ironically, a heat pump when a current is applied to it.. The Peltier effect it turns out is reversible - heat the device and it produces a current.
Not lighting up until this evening. Not expecting too much.
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Have a similar fan, Aldi, on my stove in my man cave.
Actually very effective.
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>> Have a similar fan, Aldi, on my stove in my man cave.
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>> Actually very effective.
Daughter's in laws have one in their dining room.
Having seen it in action I concur.
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We moved into our new build yesterday - very cosy. Heat pump is a Daiken. I'm using my mobile phone to post this (no telephone line) No Woodburner either.
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>> I'm using my mobile phone to post this (no telephone line)
Dog learning new tricks :-)
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Dog *loathes* using 'smart' phones for accessing the Internet.
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My heat pump is knackered! Apparently there was an epidemic fault about a year ago whereby a four way valve associated with the compressor would leak and eventually stop the refrigeration unit (that cools Hertfordshire) running. And so it was.
It will be passed to Mitsubishi who have accepted a warranty claim. I am to be advised what will happen and when, which could well be a new unit, or possibly a replacement of the peccant parts.
I'm happy in a way because, whilst it has been working, I have had reservations about the efficiency which was not hitting the claimed numbers. I had raised this previously and had a wishy washy response. With hindsight we can now surmise that is was limping along until it conked out due to lack of refrigerant and it will get sorted.
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That's annoying...
Friends of ours bought a new house with ASHP 6 years ago, they are on their 3rd unit! Original was an internal compressor, with external panels; second was a cheap external all in one; 3rd unit they put in more cash and got a 'decent' external unit - allegedly it will do a COP of 4 even below freezing.
Last edited by: RichardW on Thu 24 Nov 22 at 15:27
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>> allegedly it will do a COP of 4 even below freezing.
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Sadly all manner of factors are supposed to affect the CoP - effectiveness of emitters, positioning of collector, local wind conditions and effect of buildings, installation, flow temps, and no doubt more. So they always have a get out.
I questioned mine when in was at 2.7 in April, according the the figures displayed on its controller. They waffled around that. Through the summer it has dropped below 2, which can be put down to low loads - for nearly 3 months it was only doing hot water. But it hasn't really come back up, and before it conked it was doing about 2.
Now of course I can surmise it was running like a bag of spanners, with a refrigerant leak, so I am hoping for better when it is sorted.
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Peccant? Wondrous. Pinching it. Ta.
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First problem with the ole new heat pump ... No heat :-)
Looked in 'the room' and noticed the pressure was at zero.
Upped it to 2 bar but still no 'eating.
Called out 'the man' who found a slight leak outside on the main unit.
All okay now. Owse faces SE + highly insulated new - who needs heating?
Geezer recons Daikin ASHP's are one of the best?
Message ends.
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We're on a fixed rate with Gas and Electric until June 23, which means that at the moment it's as cheap as it ever will be....we have been planning though and have reduced our consumption by better managment (including using the Octopus energy reduction hour scheme) just to see what we can do. We installed a wood burner last summer - this has come into its own (as we hoped) warm sitting room all evening, warm hall, and warmish kitchen) Zone 1 heating is rarely used and then only with the living room radiators off. Zone 2 has its own smart thermostat which which is on for a hour or so every evening with all unused rooms having their radiators off. The undederfloor heating in the bathroom has been ripped out as we're converting this very large room (sunken bath ffs) into a modern family bathroom and en-suite to bedroom 3 in anticipation of elderly in-laws having to move in. As they're smaller these rooms will be cheaper to heat - and the en-suite ca remain unheated most of the time.
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Heating failed. And new gadget. - Bobby
