MN KPC 212-L-U/S
Product # 212.4001.03.427.0404
Problem, circuit 1 is going off on low pressure safety, also the desuperheater freezes up while it's running. Past the main TXV it's just as warm as the liquid entering the TXV (but the 1st circuit will maintain water temp aside from going off on low pressure).
We figured the TXV was bad so we ordered a new power assembly and also the guts to swap it out. Did that, changed the drier pulled a good vac and dumped the charge back in. Same thing happened.
Noticing the desuperheater is freezing up we thought maybe the txv for that is stuck wide open and robbing too much liquid causing the main txv not to have anything to flash off. We swapped that out today to no avail, same thing continues to happen.
I called tech support, we walked through the programming to ensure it was all set up like it should be (this was his last guess as to what's wrong, the tech support guy has been involved since the start). I did also check the hot gas valves were both backed out 3/4 of a turn (same as circuit to and what the factory recommends).
Prior to this I was basically a parts changer following instructions from a coworker (who on a side note isn't normally stumped by much). After that all didn't work, and watching this system operate I noticed a few things.
When circuit 2 is running, the 2 solenoids for the hot gas that feeds the desuperheater cycle quite often to keep the suction pressure around 2 bar, maybe creeps up to 2.5.
Circuit 1 will run around 1.5-2 Bar while it's trying to get the water temp down (set temp is 9.5 deg C, I let it get up to around 12 to get a good load), but once the water temp gets in the mid 9's those solenoids quit cycling and slowly the suction pressure drops until it gets low enough to shut off on the LPS.
I think there's multiple problems on this system, but I'm not real sure what.
I know the TXV should be cold right after it (circuit 2 is), and if it's not all the liquid is flashing off deeper into the evap than it should, which is limiting it's ability to pick up heat from the water and causing the lower suction pressure.
Also it almost seems like the temp sensor that controls when those valves kick on and off gets "lost". Like it's out of calibration or has the wrong settings... but it might be drifting due to the above problem too, I'm not real sure.
So do any of you Kraus experts have any suggestions?