hello guys,

We have a GSHP (brine/water) nominally rated at 31kW (heat output) supplying four apartments of about 600m2 floor area in total.

The GSHP was manufactured by ERW (Germany) in 2006.

Main component - a Copeland ZR16M3E-TWD-522 scroll compressor - R407C refrigerant, POE oil.

For several years the GSHP had been used to heat both DHW and UFH. The UFH had not been properly commissioned and the majority of the zones valves were opened less than 20%. So, heating the DHW, combined with a high temperature hot side output to the UFH (about 42 to 45 C) and low flow rates (about 30 l/min - only one circulation pump for all 4 apartments!), meant the compressor tripped out at least once daily when heating DHW, and was short cycling (more than 10 starts per hour, even in coldest winter) when feeding the UFH.

The filter-dryer indicator is showing purple = "wet" (dry/wet/caution), and the oil level in the system is probably too low - there was some green slime at the bottom of the casing 2 years ago - cleaned up, and hasn't re-appeared.

The GSHP seems to be running OK now, the UFH temperatures are (more than) hot enough in winter. DHW heating by GSHP is now limited to 43 C, then by electric immersion heater. So the compressor no longer trips, and it's maximum electrical load is about 9kW, so within spec. Hot side output to the UFH is about 38 C.

I have a couple of questions;

1. Is there any way of telling how much, if any, wear/damage might have been caused by the years of short-cycling, "wet" oil, and possible low oil level ?

2. Can the refrigerant and POE oil be replaced, along with the filter-dryer, in situ, and would it be advisable to do that ?

The German manufacture is asking € 1,100 just for travel/hotel costs (they're based about 4 hours drive from us), so we're thinking of getting a local air-conditioning/refrigeration company to do any work.

Thanks in advance for any advice.

Greetings from Brussels

Chris