High Amps on Chiller Compressor Motor

[MFJewell]

I am experiencing an issue with one of the chillers at my facility and am looking for some insight. The unit is a 1974 vintage Carrier 17DA unit. It is nominally 5000 tons (holds 15,000 pounds of R-134A).

We took it down for maintenance and have been experiencing 100+ amps higher draw on the motor after the maintenance. Both the evaporator and condenser were opened, cleaned, and eddy current performed. We removed the charge from the unit, dried it out and put it back in. Motor was not touched.

Before the maintenance, the unit had the following parameters: Chilled water flow of 8300-9000 gpm, 3800 to 4000 tons, 360-390 amps, guide vanes at 28-36%.
After the maintenance, the unit had the following parameters: Chilled water flow of 5800-6300 gpm, 3000 to 3300 tons, 450-485 amps, guide vanes at 41-49%.

We ran the unit in single pass and still had high amps. Put it back to double pass and confirmed the chilled water flow meter is correct, Sub-cooler level is good, hot gas bypass is full closed, evap dP is good. We have no abnormal noise or vibration from the motor and it megged good. I believe all of this seems to point towards an overcharge or refrigerant in the unit. Anyone with experience similar to this and have feedback on what to check next?

 

[MFJewell]

Most likely 13-14,000 GPM when we were running it before based on amp draw.

A little side note, operations attempted to do a test and force as much water through it as they could. They then started a second pump with no other chillers online and blew out the division plate. It bent a 1" thick with structural c-channel reinforcement into a U shape, the tore the bolts out. When they were trying to run the unit the next day, I saw zero dP across the evaporator with the unit surging, so knew something was wrong. Had my guys check the plate through an inspection port the next morning and found the damage.