COLL Fault

[torrman]

Hi,
Working on a chiller with a cvm300 panel and displaying coll which is loss of communication between pcb and display.We have fitted a new pcb/transformer and front panel and also ferrite rings to pretty much all cables inc comms however it still appears after a few hours.
Has anybody had this and managed to overcome the fault ?
Thank you

[frank]

To be quite honest, I haven't a clue what you are talking about.

[torrman]

Hi,
The cvm 300 is the control panel,the pcb is the motherboard and the chiller is a Hitachi complete with 2 screw compressors.

[mchillerman]

Hi. Being an ex ICS tech service manager and alround Climaveneta tech, your problem lies as follows.

The safety circuit for the condenser fans run back to the PCB. This should be only a low voltage signal out through the fans and back. You will find that one or more of the fans has a winding issue, which in turn is allowing excess voltage back into the PCB on this safety circuit. To confirm this temp remove the fan protection circuit cables from the CVM 300 PCB and replace the out to in cable with a shorting link. Run the chiller, you will find no further COLL alarms will occur.

The fix. Either locate the faulty fan and have it rewound or fit OLs to the fan contactors and run the safety circuit through the aux contacts. You should also run the contactor supply through the fans own internal thermistor.

If you need any further help with Climaveneta / CVM controlers give me an e-mail. martin.fairchild@elite-refrigeration.co.uk or mchillerman@aol.com