Rhoss Chiller

Hi all

I have been working on a Rhoss chiller Mod: TCAVB2045010247
R407c screw compressors 2 circuits.

Ive had Hp pressostat faults alm16
lots of issues, ranging from blocked gomax to transducers, faulty main contactor as star delta config.
The system starts ok usually and runs on head of about 15bar to 19bar.... Hp switch is set 25bar man reset.
All of a sudden the circuits will shutdown and trigger a Hp pressostat alarm????? When I check the switch it hasn't broken, also thermistor module is ok.... seem to trip when pressures are ok.
I have replaced the pcb for comp 2 which was faulty not outputing to run comp.....

Would be grateful for any info advice if anyone has had similar faults.....
I have called chiller4service but tech assist not much help.

Regards
Darren

can u test the hp switch to see if it does trip at the 25 bar rated pressure- may be out of sync- best to test with nitrogen if possible

Мммм, unit have big red button like "emergency shutdown" ? Usually press the button initiates an accident at high pressure and turning off the unit.

Check the Hp switch circuit again,

The Rhoss chiller I worked on a number of years ago had a dual HP switch.

one part of the switch was auto reset, the other part of the switch was the manual reset.

Thanks for replying... Yes I guess I could test it when next on site but as its a mechanical HP/LP switch you can clearly see it hasnt tripped and electricall has a circuit through it.

No big button just standard carel keypad

Thats correct. Its an alco mechanical switch. Auto LP man HP but clearly not tripped Thanks anyway

had an issue with an hitatchi vrf- occasionally alarmed on hp failure- but all checked out ok, after a week of swapping hp switch,sensors,pcbs finally suspected the alarm relay- swapped and no problems- weak coil was the culprit- system was 8 yr old - just thinking outside the box:)

Had this on a mercury unit with a Carel unit retro fitted to it.
When it was fitted one of 4 available HP I/O's was used for a fault from a fan speed controller.
Took a while to figure it out.
Interrogate the controller programing and check for hp transducer limits !!
Cheers
Stu

cool. Thanks for that I will change the parts ive condemned then will take another look. :)

thanks Stu good1

Hi
if this unit uses a carel pco controller then the hp input 230 v is faulty , either id13h or id14h
you can swap inputs and change to 24vac on the same input accordingly using the id13 or id 14 depending.
good luck