Trane Heat Pump Problem

phk

I need some advice on fixing a problem with compressor failure.
Trane TWA180 heat pump, dual unit 7.5hp compressors.
These are older heat pumps no accumulator, no oil seperator, has the basic filter driers, RV etc.

I have seen three compressor failures in 5 years, two in the same unit.

The lineset is about 120'. After reading another post about solenoid valve install on longer linesets i was curious about installing them on these units.

There is two dual units a total of four compressors.

In the process of replacing one currently. Have installed an accumulator and oil seperator to hopefully prevent another failure.

Should i install a solenoid valve?

Any input would be great. Thanks!

artco

Is the condenser above or below the air handler?

phk

The air handler is inside a mechanical space on the second floor, and because of the space being enclosed it is much warmer than the condensor. Condensor is located on the ground level with no enclosure, about ten feet below the air handler and about 60 feet away, lots of pipe!!

artco

I would double check to see if the piping requirements meet Tranes recommendations. (Trane piping manual)

Make sure the crankcase heaters are working. This will help prevent liquid from building up in the compressor when sitting idle thus preventing oil from washing out at start-up.
Rotarys are pretty strong for pumping even liquid but the problem is the liquid takes out the oil for lubrication resulting in compressor failure.

Did anyone check to see if the oil in the failed compressor was low or gone?

Was the first compressor a burn out?
If yes was the system cleaned and suction filter installed.

Have all the compressors failed for the same reason?

The installation of a solenoid valve can be done providing the valve opens when ever the compressor is energized.
I looked at the recommended controls for that unit and there was no mention of a solenoid valve required. I know solenoids have been used in fact we used them on a few installations.