View Full Version : Bitzer screw compressor sticking unloader?

09-04-2016, 05:09 AM
Hi guys just looking for some help with a bitzer screw compressor. Model is cah8571-140y-40d.
The screw is running a chilled water system. The system starts the compressor up for 20 seconds in 25% capacity before switching to 50% it shifts to 75% if water temp rises above 16 and full load if above 18. I'm having an intermittent issue where the 50% solenoid is energised yet the compressor current draw is showing full load. I've come to the conclusion that the 50 solenoid is sticking in the closed position occasionly. I've tested voltage on the coil and it is magnetised when the issue is occurring. The problem we are having is the compressor is cycling too often and switching off at full load.

09-04-2016, 07:16 AM
Have you checked solenoid, pulled it apart, swap it over with another?
I think you have to try that first.

13-04-2016, 07:14 PM
Hi rarely have I had a Bitzer solenoid stick.
u should have 4 of them so u can swap the heads to make sure as said above .
why aren't u using continuous control ?
if at 75% u are showing full load I think u have a different problem .