Air Source Heat Pumps

albyota

Yep, agree with zeupater, heat pumps should not be controlled like conventional boiler systems, also UFH needs to be heated almost constantly, aided by night set back room stats. I think that the way you are controlling it is not allowing the UFH slab to get up to temperature, along with trying to raise the hot water cylinder temp, my advice would be, to persevere, set the room stat to 21, use the immersion heater for the moment to heat the domestic hot water cylinder, yes initially, you will use a lot of units to get to this temperature, but it should decrease as the inside temp increases.

My house is 185m2 with UFH set at 35 degrees, I have a 8.5 kW Ecodan heat pump, it is currently 8 degrees outside, 22 inside, heat pump is running and drawing, 1.2 kW constantly, well until about 10.30 pm when night setback to 17.

If your system is found to be set up correctly, then you must try to put aside the initial high running cost to get it up to temp, as you will find it will be an efficient system.

By the way, the HP AW110 seem to be sized correctly, at 69% @-3'c if as you suggest very high levels of insulation, DG, UFH on the ground floor and correct sized rads upstairs, you should only be running at max 45 degrees.

AL

lovesgshp

albyota wrote: »

Yep, agree with zeupater, heat pumps should not be controlled like conventional boiler systems, also UFH needs to be heated almost constantly, aided by night set back room stats. I think that the way you are controlling it is not allowing the UFH slab to get up to temperature, along with trying to raise the hot water cylinder temp, my advice would be, to persevere, set the room stat to 21, use the immersion heater for the moment to heat the domestic hot water cylinder, yes initially, you will use a lot of units to get to this temperature, but it should decrease as the inside temp increases.

My house is 185m2 with UFH set at 35 degrees, I have a 8.5 kW Ecodan heat pump, it is currently 8 degrees outside, 22 inside, heat pump is running and drawing, 1.2 kW constantly, well until about 10.30 pm when night setback to 17.

If your system is found to be set up correctly, then you must try to put aside the initial high running cost to get it up to temp, as you will find it will be an efficient system.

By the way, the HP AW110 seem to be sized correctly, at 69% @-3'c if as you suggest very high levels of insulation, DG, UFH on the ground floor and correct sized rads upstairs, you should only be running at max 45 degrees.

AL

Think there is a little confusion over this pump. In an earlier post, the OP stated this:
I've had a quick look outside the house and the pump only outputs 8.73kW which seems low?
This seems to point to him having the HPAw85 from the user manual and not the AW110., whose output is over 11Kw.

The OP also stated that there is only UHF in the bathrooms and the rest of the house is radiators.
" What I can tell you at the moment is that it's a Grant Aerona pump (HPAW110 I think, but will confirm later) feeding radiators in all the rooms and UFH in the bathrooms."

In light of that, then the 40C temp in the tank would point to the unit never being able to reach suitable rad temps, to achieve a 21C internal temperature.

albyota

Baz@rr wrote: »

.......What I can tell you at the moment is that it's a Grant Aerona pump (HPAW110 I think, but will confirm later) feeding radiators in all the rooms and UFH in the bathrooms.

Apologies Geotherm, so no UFH other than the bathrooms, although, he states the AW110, 11 kW unit, this is worse than I thought. If it is struggling to get up to temp, and using 70 to 100 kWh / day then bazz@rr must put landlord under pressure to get it removed / replaced

lovesgshp

albyota wrote: »

Apologies Geotherm, so no UFH other than the bathrooms, although, he states the AW110, 11 kW unit, this is worse than I thought. If it is struggling to get up to temp, and using 70 to 100 kWh / day then bazz@rr must put landlord under pressure to get it removed / replaced

To be quite honest, from the info I think he still has the sub 9Kw pump, which may well be undersized.
Agree he must get some answers to the problem, as Winter is now starting to get in full swing.

Baz@rr

Sorry all, day of disasters so quick reply via phone before i run out to hospital again.

Just to confirm it is the 8.73kW unit. The UFH has not been on and we have had the main heat thermostat set to 19 for the past couple of days, so not high by any means.

The heating has actually been on for over a month before we moved in, so this isn't a case of the system just getting up to temp.

As if all this wasn't bad enough, a valve at the cylinder stayed leaking today and we only noticed when it started coming through hall ceiling. Water is now shut off until plumber can get back at 6.

Joy.

Baz@rr

And sorry, to clarify, UFH is only in bathrooms. Rads in the other rooms. Actually there ate rads in the bathrooms, too.

lovesgshp

Baz@rr
Hope mother is getting better.
Keep us updated as to how things are going

albyota

Baz@rr wrote: »

Sorry all, day of disasters so quick reply via phone before i run out to hospital again.

Just to confirm it is the 8.73kW unit. The UFH has not been on and we have had the main heat thermostat set to 19 for the past couple of days, so not high by any means.

The heating has actually been on for over a month before we moved in, so this isn't a case of the system just getting up to temp.

As if all this wasn't bad enough, a valve at the cylinder stayed leaking today and we only noticed when it started coming through hall ceiling. Water is now shut off until plumber can get back at 6.

Joy.

OK, enough speculating, you clearly have a house built to very good standards, which has been fitted with an undersized heat pump, and not, IMO, one of the best makes. Your landlord has been mis-sold this heat pump.
You now have to gather all this Data and info from all of us on MSE and pressurise the landlord to ask questions, and get this resolved ASAP.
If he needs to speak to someone independent, give us a shout.

Good luck with it, hope you get it sorted, keep us posted.

AL

lovesgshp

albyota wrote: »

OK, enough speculating, you clearly have a house built to very good standards, which has been fitted with an undersized heat pump, and not, IMO, one of the best makes. Your landlord has been mis-sold this heat pump.
You now have to gather all this Data and info from all of us on MSE and pressurise the landlord to ask questions, and get this resolved ASAP.
If he needs to speak to someone independent, give us a shout.

Good luck with it, hope you get it sorted, keep us posted.

AL

We can always only speculate on a lot of the info, unfortunately. But hopefully point the user in the right direction. Pity we do not have the heat requirement details for the houses we try to answer on!!
I do not know the Grant pumps, so the answers are based on my own views.
Glad you have had experience with them!!! Would have thought that if it was the 11Kw unit, then performance may have been a little better.
There are so many old style heating companies getting into the heat pump market, that there are sure to be problems.

Cardew

The owner should exchange views with Tired Geek(who also has a property in Scotland) about how to get redress.

I will resist the temptation to comment further!!