Ground Source Heat Pumps

beardymarrow

lovesgshp wrote: »

Hi Beardy.
If the additional heat is activating, then the 60 min countdown has activated. You could try altering it to 2hrs, or alternatively turn off the add heat as a test to see what temp the compressor is reaching.
What is the room sensor influence and temp?
Can you overlay the outside temperature on the graph?

Thanks lovesgshp,
Yes, the 60min countdown does indeed kick in (if the compressor can't get GT1 above the target). For the period between 20:00 and 04:00, for example, GT1 sat at 38.4deg, with the compresson on and without add heat kicking in (so that's basically the test for what temp it can hit without add heat).

Room sensor is set at 19.5, influence 5.

Graph with GT2 added on it below. You'll see it was roughly a flat 2.2-2.3deg.

Link to larger version

External temp doesn't seem to have a huge bearing as between 09:00-15:00 the previous day, you'll see GT2 goes from 9deg down to 5deg, but GT1 stays flat at 36ish (again with the compressor on solid and add heat off).

Just to be clear, I'm not worried about add heat not kicking in as I understand why it hasn't. What bothers me is that the compressor is on solidly for 8 Hours, and it still can't raise GT1 above 38.4.

lovesgshp

Give me the heat curve settings from 10C to -10C.

beardymarrow

lovesgshp wrote: »

Give me the heat curve settings from 10C to -10C.

Hi,
10 = 28.8
5 = 33.0
0 = 37.2
-5 = 41.4
-10 = 45.6

Curve is 5.3 with no breaks. GT1 tgt is higher than the curve at the moment as room temp is lower than required.

You'll have to excuse my ignorance, but I don't understand how the curve values will affect the temp that the compressor is able to hit on its own?

lovesgshp

Try changing 10 to 35, .. 5 to 35.

beardymarrow

lovesgshp wrote: »

Try changing 10 to 35, .. 5 to 35.

Thanks. Done that. GT1 Tgt is currently 42.3 (On 39.8, Off 44.8) including the influence of the room temp.

lovesgshp

Is the additional heat operating as well?

beardymarrow

Hi,
Yes it is coming on until gt1 hits about 43 when it switches off. Gt1 then drops to about 40 and then add heat comes on and the cycle repeats (cycle takes about an hour) . Compressor is obviously also permanently on. It's the same as it's been doing since about 9 this morning.

lovesgshp

Turn additional heat off and let me know how it goes.

beardymarrow

Hi,
Turned off add heat last night at 21:00. GT1 then dropped slowly to approx 38.5 at 03:00. At 03:00 DHW production kicked in, and GT1 dropped to approx 31 while DHW was produced. Once DHW had completed (approx 30Mins later) it then rose to approx 36 and sat there until 08:30 when DHW was again needed.

Link to bigger image

PS GT8/GT9 (hot side) Delta is 7.1, so in the right range (7-10 according to the manual). Lowering P2 causes it to go to about 11, which is too high.
GT10/GT11 (cold side) Delta is 3.5, so again in the correct range (2-4 according to the manual)

lovesgshp

The deltas are fine.
Compressor is obviously working to a higher temp for hot water production.
If you have not done so, check for any alarms, as there could have been resets.
Confirm that all circulating pumps are working.
Would you also supply the graph for the 28th, which was before the problem occured.