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VärmepumpsForum Allmänt => Värmepumpar - Märkesspecifikt => Värmepumpar - Mark/Berg och Sjövärmepumpar. => Värmepumpar och installationsfrågor. => IVT => Ämnet startat av: Carl W skrivet 03 februari 2019, 23:54:17

Titel: IVT C7 low delta on G8 and G9
Skrivet av: Carl W skrivet 03 februari 2019, 23:54:17
I've read the history on this forum with interest and some very valuable information has been shared, I've been unable though to find someone with the same issue as I'm presently having. It's my first year in a 6 year old house which has IVT Greenline C7 system with underfloor heating up and downstairs. Running hours have appeared to increase since moving in 8 month ago, were as now the compressor is running 20 hours a day and not really getting the house hot (but just getting it warm).
The Unit is Rego637W and has 18790hours, and 411 hours of additional heat, I note in the last 12 months it's done 2500hours and 119hours additional heat.
My main concern seems to be the delta drop G8/G9 of only 3-5 Deg, whereas the manuals and info on this forum all state it should be 7-10 Deg (max 11 Deg). During heating cycle after system running for 10 minutes and 20 minutes below are the readings
Heat curve 5, fine adj +2, (normally heat curve 4 and fine 0, I only raised the numbers for ongoing testing)
GT1 off 41.2 now 32.2 / 20mins - 40.2 now 33.3
GT2 4.4 / 20 mins 4.8
GT3 That 48, now 48.3 / 20 mins - 48 now 47.8
GT5 That 22, now 21.2 / 20 mins - 22 now 21.3
GT6 64.1 /20 mins 70.5
GT8 36.7 / 20 mins - 37.9
GT9 32.3 / 20 mins - 33.4
GT10 1.8 / 20 mins 0.9
GT11 -1.7 / 20 mins -2.4

Pump speeds, bypass fitted and fully open
Ground source pump III
Circulating pump II
Downstairs underfloor circ pump II
Upstairs underfloor circ pump I
I have tried to change and monitor pump speeds and find above pump speeds give out the most heat. In addition I've removed and cleaned all flow meters on all the floor loops so these now work correctly.
I've reflushed entire system, no air found, cleaned all hot and cold filters, no dirt or solids found.

The compressor has bubbles at the sight glass only for the first minute and when changing from DHW to heating. The expansion valve does show ice on the adjustment head end after 30mins of continuous operation.

There is no alarms in the system during operation at all.

If the additional 3-6 KWh heat comes on I then get around 7 Deg delta on G8 and G9, and floor heating does increase.

If someone can provide guidance it would be much appreciated before I call in the high cost service agents.  Thanks Carl
Titel: SV: IVT C7 low delta on G8 and G9
Skrivet av: Carl N skrivet 04 februari 2019, 07:47:28
Hi!
I think you need a refrigeration technician to check up the heat pump, my suspicion is that it is the expansion valve that don't work properly.