View Full Version : Ciat PRS1 control problem

19-07-2016, 09:11 AM

Due to a faulty display on a "ciat LW M 1600z 2" I was forced to replace it. After the switch I have noticed that the machine can't manage to get down to the desired setpoint (as it did before). The machine goes down to 0.5 degrees from setpoint but never stops. I reckon it's a problem with the capacity regulation because the capacity used lowers when the water temp lowers but it never gets down to setpoint. It may be a small problem but as it never stops it can't switch the running compressor either so I'm currently only using one comp all the time. I have checked every parameter I can think of but I must be missing something. (Another weird thing is that I cant access the parameter p24 which is the parameter for min position of slide valve.)

Has anyone had the same problem before? Anyone got any pointers?

Kind regards


19-07-2016, 07:00 PM
Your compressor is CSH or HSKC?

19-07-2016, 09:02 PM
It's a HSKC (two of them).

20-07-2016, 07:47 PM
HSKC doesnt have slide valve. You mentioned your leaving water T is just 0.5 C below setpoint?

21-07-2016, 07:23 AM
I really think it got a slide valve. I can be wrong about the model because I just checked google and compared to a pic I got. Which do you think I have? 14205

No temp only gets down to 0,5 C over setpoint but never gets the down to setpoint as it did before the display switch.

21-07-2016, 09:54 PM
It is HSKC. Controls capacity opening bypass inside compressor. You control water on inlet or outlet?

22-07-2016, 05:35 AM
Oh okay, I just took for granted that there was a slide valve. We control on inlet temp.

25-07-2016, 04:55 PM
Play with P36, P37.

26-07-2016, 06:43 AM
Okay, tanks! I will try that