Heat Pumps - post here.

@Tar.Aldarion It shouldn't behave like that. You should have piping hot water if that's what its setup to do. The house dropping to 17°C also isn't right/normal/acceptable.

You need to get an engineer out to look at the system and see if the settings are right or if it has developed a fault.

Any red lights or warnings or alarms on the screen of it? Either way, get someone out to look at it.

Bit of an odd question, my kwh usage on heat pump mental. Sitting room in particular always calling for heat and never gets to 21 and i have just turned it off now. Essentially When the sitting room calls for heat the utility next to it has no heat change as its ran on kitchen stat but the main bathroom beside utility gets v warm. Is it possible that my sitting room stat is heating the ufh in my bathroom while by passing the adjoining utility and heating bathroom. IM starting to think the sitting room stat is just heating bathroom and not the actual sitting room its meant to heat. Cant understand how pipes would be laid out that the sitting room pipes get warm, adjoining room by passed and then main bathroom warm.

Is there anyway to check this or fix it? been driving me mad with months, had stove in sitting room so just presumed that room would never get up to21 with flue, but the bathroom would get roasting as sitting room stat was calling for heat for days on end. I coud see 2 actuators up and flow going when sittng room stat on but only bathroom which has no stat seems to warm up.

yeah have manifold and when sitting rooms stat comes on, 2 actuators pop and flow rate starts. Hard to feel the timber floor for heat in that room but i know by temp not increasing something is wrong and bathroom floor gets hot. Dont know why they would have rigged sitting room and bathroom on same stat as them rooms not near each other. Kitchen stat does utility and hallway and half way up is the bathroom which come son when sitting room beyond kitchen calls for heat. Can this be easily rectified?

The manifold, stats and actuator issue is easily rectified but the key bit the process of elimination to understand which run from the manifold is heating what room. One stat at a time, what heats up in terms of pipe at manifold and floor of room.... Once that's done its hopefully just a case of unscrewing actuators and putting them on the right manifold section. Doing this way avoids any need to touch stats or electric side of things.

Thanks for all the info here. Had guy out servicing my boiler yesterday too and was telling him about kwh usage. He said my dhw temp at 50deg was too hot and i should bring it down to41, Anywhere i read online it says 50. Was his suggestion correct? Tried it on my daikin and put to 41 but it keeps going back to 50 after a while.

It depends on the type of heat pump.

Air-to-water systems will go to <100% efficient in really cold weather as they have to use up energy to defrost themselves.

Ground source systems dont suffer from that as the cold/frost doesn't affect the pipes under the ground. e.g. it could be -5°C outside in the air but the pipes under the ground are sitting at 5-10°C so that's an immediate gain of 10-15°C that the ground source system does have to "find" relative to an air-to-water system.

Ground source should provide a COP of 4-6 during the winter. This makes it a more efficient and longer lasting system as the compressor is under less stress when heat is needed the most. The downside is they cost more to install. Thats a balance you have to strike when you are installing.... unfortunately most people go for the cheaper install option because its the cheaper quote they have, rather than looking at the lifetime cost.

Of course, some sites just dont have the space to install ground source systems, which is fair enough too.

A properly designed one should still have a COP over 1 in cold weather

Mine unfortunately doesn't have the ability to read the COP but I remember I calculated it a while back and it was fairly close to what the manufacturer was saying, around 2-2.5 for this weather

As others said the defrost cycle uses some energy, mine takes the water from the buffer to do this so it has to recharge the buffer again afterwards

If it can supply enough heat without using the backup heater then it should stay pretty efficient. Avoiding the heat pump cycling on and off seems to be key as well

Having the flow temp low and long heating cycle seems to be the answer to that

The sitting room stat seems to just make bathroom hotter and sitting room temp doesn't rise with any stat. Utility which is between bathroom and sitting room gets hot with kitchen stat which is adjacent to sitting room. surely the the pipe run couldn't be that short to run from plant room to bathroom beside it and back again when i turn on sitting room stat.

Pics of the manifold would help.

Number of stats downstairs?

You could have broken actuators, stat linked to wrong actuator.

Poblem definition is important. First thing is it seems your kitchen stat controls the bathroom actuator. But it's the rest of the config that needs to be established before you go swapping anything. The actual fix could take a minute or two once you nail down the problem.

Runs can be long or short. Downstairs I've 6 runs, 1 for hall, 1 for sitting room, 1 for utility and connected bathroom and 3 for the kitchen / living room area (50m² for this room hence multiple runs I guess).

Its a bungalow 7 stats in total.Im going off to Vegas in the morning so will take pics of the manifold when im back next weekend. Appreciate all the help here. The lad that done my boiler who told me he would explain everything was pretty useless and cost me 250eur for an hour of his presence.

My heat pump used just under 600kWh in November and December combined. That's for heating and hot water and probably 85%+ was on night rate (would have been 90+ bar those really cold December days). Probably about 200 m² house. A3 rating post refurb. Triple glazing with UFH downstairs. Well insulated but a bit of remedy work due on air tightness (mainly around vents in a few rooms).

Everyone's insulation levels, air tightness, glazing etc. And the quality of installation of all of that and the heat pump are a factor, as well as the installer knowing the unit they are installing well to configure accordingly.

Well most of your heating load is probably going to be at night when it's colder

FWIW, yesterday my house consumed 43kWh from the grid, but I'm pretty sure 13kWh was for my wife charging her car. So probably around 20kWh for the heat pump, most of it at night

You can also get heat pump integration with solar PV, so it can do things like prefer to heat when there's excess solar PV

Thanks all for the info being posted.

Hopefully having an air tightness test next week. Need to go round the house with a fine tooth comb to seal those last few penetrations, pipes into the attic from hot press being one.

That was one of the coldest days of the year so far to be fair

Is this just doing your space heating or is doing you hot water showers as well?

Just to let you you know I have a Joule/Samsung 12kW system which does all my heating and hot water for a 200m2 A1 rated house and I used 600 kWh so far in Jan...you might not be that bad..

Unless Im doing terrible but I am watching it and I dont think so. Dec/Jan will be your most expensive months anyway you are just shifting oil or Gas kWh into Electricity.

If it's an area you are happy to spend then a ground source is more efficient than an A2W but not always practical for a refurb, but might be for a new build. Could be mistaken but reverse cycle is typically heating inside the home as in standard in this part of the world.

If your insulation and air tightness is to spec you'll need to think about how to cool place down in rooms you've any south facing windows. I'm heading towards AC at this stage I think. Hopefully with solar panels to make the cooling "free"