Cope Scroll and GD chiller

[Richvacr]

I took on a job at a new place on a chiller in a brewery - GD13.5H with a replacement Copelandscroll ZR125kce... 3 PH. Yes that wasn't the original Maneurop. The at least 2nd compressor was the ZR125 which was shorted to ground and it so happened a new one was on roof for the past few years just not installed. Anyhow I but it in w/ new drier. Charged with 50lbs R22 going good. Went to test pump down switch to make sure it CO at a good pressure, it didn't also then found control wiring kaka - low pressure switch in series with solenoid. Returned everything to mfg tstat controls solenoid & LP compressor contactor. Now suction pressure drops from 25 psi to CO 10psi and head pressure doesn't raise. Held in contactor to see what happens the same low drops to 0 and fluctuates between that and 5 psi and head pressure might move 1 psi or nothing. Also no sign of movement in sight glass, refrigerant about 98% full with little bubble at top. Running relatively high amps 26-28A but under RLA 32+-.

Any ideas what might be going on?

Tomorrow ideas are maybe add a few pounds R22 into low and see if high side goes up.
Recover and flow nitrogen to see.
Oil logged Evap?
Bad valves? But why good suction?
The fluctuation doesn't sound good either.

[Richvacr]

Also there is a valve up from suction inlet we closed this and ran compressor and the same fluctuation 0 to 5 with in seconds

[frank]

Have you checked for correct rotation of the compressor?

[Richvacr]

Have you checked for correct rotation of the compressor?

Low side drops and when reversed it doesnt

[seanf]

Anything like liquid injection or an oil return on the comp suction or crankcase?

When running in cooling, whats the pressures and temps for suction, discharge, liquid line, inlet and outlet temp of fluid being cooled, air on and off temp of condenser?