UPDATED: Air Source Heat Pumps/Air Con - Full Info & Guide, is it cheaper to run than mains gas?

lovesgshp

This is suggestion, turn the setback to 19C.

richardc1983

lovesgshp wrote: »

This is suggestion, turn the setback to 19C.

Could you explain the benefit to this other than the house will be a degree warmer during the night?

lovesgshp

What I am working on, is return flow temperatures. There should not be a drop of more than 4C on that for a rad system.
Can you monitor the temperature for the return flow, when you are set at the lower temperature during the day?
What I think is that it may be going too low so the pump is having to work harder to get to room setting at 21C.

richardc1983

lovesgshp wrote: »

What I am working on, is return flow temperatures. There should not be a drop of more than 4C on that for a rad system.
Can you monitor the temperature for the return flow, when you are set at the lower temperature during the day?
What I think is that it may be going too low so the pump is having to work harder to get to room setting at 21C.

We've already been told that the flow rate should be 30l and we're getting 16 hence the big drop. The pump doesn't know what indoor temp is at the thermostst. It will just call for heat or not.

Outside temp currently 1c, flow is 43.5, DHW is 45?? (No hot water has been used since the last readings so this seems to be dropping quick) return is 33c. Temp in rooms are 20.5c in living room, 20 in hall. Upstairs is Prob about 21c due to heat rising. All rads nice and hot - well 43.5 lol.

lovesgshp

How long have the rooms taken to reach those temperatures and is the pump running constantly at the moment?
With your DHW, think the switch on would be @ 44.9.

richardc1983

lovesgshp wrote: »

How long have the rooms taken to reach those temperatures and is the pump running constantly at the moment?
With your DHW, think the switch on would be @ 44.9.

Yes running constantly and since 5pm.

lovesgshp

Can you override the thermostat and just use the TRVs to control the room temperatures? Have they got bypass valves fitted?

richardc1983

lovesgshp wrote: »

Can you override the thermostat and just use the TRVs to control the room temperatures? Have they got bypass valves fitted?

Well yes I guess you could but then it would be on all the time. A couple of rads and the Kickspace heaters are always have flow through them.

lovesgshp

The problem I am seeing, is that when you drop to 18C then the return flow goes far too low. As you say, it gets to 16, so therefore it is having to work at max to get back up to the room temp of 21C.
A 3C room temperature change within a few hours is quite a lot.

richardc1983

lovesgshp wrote: »

The problem I am seeing, is that when you drop to 18C then the return flow goes far too low. As you say, it gets to 16, so therefore it is having to work at max to get back up to the room temp of 21C.
A 3C room temperature change within a few hours is quite a lot.

Im really confused where did you get 16c from, at night set back the system only comes on if it needs to the circulating pumps are off during this period. If the temp drops below 18 the outdoor unit will then fire up but based on the thermostat in the hall.

Really appreciate your help so far.