The other day I went to stop a RTAC250 to do an inspection. As circuit #1 was shutting down I got a diagnostic “Pumpdown Terminated.” In checking the IOM I was left a little bewildered. The explanation is somewhat vague. What are the “specific set of diagnostic criteria?”
I know that below 50*F OAT these machines do what is called an “Operational Pumpdown.” The explanation on that in the IOM seems to be incomplete. I even checked the latest and greatest IOM on Trane’s website and the explanations are exactly the same as my original IOM that came in the unit. This particular unit is a 2009 with version 30.0 software.
Unfortunately, I was not on the Refrigerant Screen to see what the pressures or liquid level were doing at the time. I was hoping that maybe you Trane guys or RTAC experts could shed a little light on these explanations.
From the IOM-----
The circuit is in the process shutting down by performing an operational pumpdown just prior to stopping the last running compressor. The EXV is commanded closed. Pumpdown will terminate when both the liquid level and the evap pressure (where's the rest????)
Pumpdown Terminated - Circuit 1:
The pumpdown cycle for this circuit was terminated abnormally due to excessive time or due to a specific set of diagnostic criteria - but w/o associated latching diagnostics
I appreciate any help.