Airedale Fault

[Davmarr]

HI
Anyone help, been looking at an airedale ACC 120 D chiller 2 comps 4 stage. unit runs ok then "faults" the comps unload and shut down, as they are doing this the fault clears and it all starts up again run for a bit and faults again. No indication on the Trend panel what the alarm is , all running pressurs are ok when its running. The prob is its just not telling us the fault is.

[pavilion]

Is this chiller controlled from a BMS system, if so are the run request signal cables healthy?

Pavilion

[MTX]

The only fault that I have had on these chillers that dont show as a fault are oil pressure. Also check the control protocol is it in local on/off?

[Brian_UK]

As MTX says, check the control strategy.

Some controls will ramp up and down in percentage points. The cooling could get turned ON at say 65% of signal.

The temperature then changes slightly and the signal drops to 62% and the cooling is turned OFF again.

This is the worst type of control for compressor operation. You need a wide deadband to ensure that the compressors get a decent run time.

I've lost two compressors before due to that type of control.