I have a couple of Trane Axiom High Efficiency Console Water Source Heat Pumps which stop working with what seems to be a high pressure lockout. i.e. the compressor comes on, runs for a few seconds, pressure switch trips, and then the unit shuts off.
After bleeding a lot of air from the water pipes, the units operated for a little while, but this time cooling was periodically suspended due to high water temperature.
Hours later, both units seem to be suffering from the same original issues again (pressure switch tripping). They were installed around the same time (2003). There is also a gurgling sound from the water pipes when the units are not running, which I guess is from air bubbling through.
One explanation is that this could all be due to air in the water or low water pipe flow.
Another could be that it is due to an old unit, which will effectively require replacement.
Is there a way to decide between the two options, other than replacing the unit and seeing it continue to fail?