Trane 7.5 ton heat pump RTU

[pherman]

7.5 ton heat pump trane 230 3 phase unit had a bad compressor, replace compressor, dryer, weighed in charge. In cooling it pumps down (to 0 psi on low side) and shuts off on safety. In heating mode pressures are ok (75/300) and amp draw is ok 30. Checked with trane they said check orifice at evaporator to make sure its not restricted. Checked and cleaned it (not sure what the tech used I left at that time) but said it was clear. Same problem when recharged unit. In cooling the liquid line to evap is cold like there is a restriction in the condenser. Is there any other check valves or orifices besides at evaporator? Sorry such a long post. Any ideas would be appreciated.

[jsherhvac]

sure you installed a bi flow drier??

[pherman]

good question but positive it is a biflow

[BobbyBJr]

You didn't post a model number, but almost every Trane I can remember seeing had two driers in the outdoor unit, one for heating and one for cooling, and the checkvalve. Did you replace those driers, take them out and straight pipe, or what, when you put in the bi-flow? Is the liquid line service valve fully opened? Just some ideas.

Bobby

[pherman]

sorry its a WSC090A3. There was only one dryer on the unit and was located in the outdoor section at the condenser. Per Trane a biflow dryer is apporved replacement for their dryer (didn't use the OEM dryer). No service valves are closed. The part that I cant get is in heat its OK and doesn't trip any safety. Only in cooling. The press drop fast too. The only places I could think of restrictions were at the dryer or evap orifice.

[pherman]

Went back today. Found the problem if you all are interested. The check valve at the outdoor section was bad and was acting as the metering device. All is well now. Gotta love them Tranes