Costan multideck chiller tripping.

[Smiler]

Hi, I attended a call to a Costan multideck chiller tripping on the cabinet and taking the mains out too.

When i flicked the breakers back on the cabinet ran perfect and pulled down to temp. I monitored it through a de-frost and there were no further issues, with it tripping out, the 2 compressors were not pulling any extraordinary Amps and there was nothing in the controll panel un-to ward.But this was a 2nd call out to the cabinet!

Has any one any ideas?

[philfridge]

Hi I would sugest you should test the electrics with a megger and report back with the results

[Kp3]

is the supply 13amp plug top? if so both comps could be starting up at same time cause it to trip. there should be some kind of time delay on it to stop this happening. is there a vapour tray with float switch for the heater? check what philfridge has said also

[Gary]

I would be looking for a nicked wire and a burn mark where it touched grounded metal.

[Smiler]

The compressors start up with a delay between each other.
There are 2 vapour trays with float switchs for the heater.

[Electrocoolman]

When it 'takes out the mains', is it just the circuit that its plugged into, or are we talking about the whole power (i.e. RCD?).
My bet is that its just the circuit that its plugged into.
As is normal in these larger cabinets, its got two compressors with a starting delay between the two condensing units.
The question is has it got one or two 13A plugs, or is it hard wired into the power circuit?
My bets are that the start delay unit is faulty, or maybe there is a problem with one of the compressor starting circuits.

For example, if the first compressor tries to start, but has a 'lazy' relay or capacitor, it doesn't always start but sits drawing high current before it cuts off on thermal overload, during which point the second compressor then tries to start....the resulting current is too great for the breaker.
The other question is what type of breaker is it....B, C or D?

[lowcool]

phill has it right it could be moisture or anything else until you can be satisfied that it is not the cabs then move on to power supply.i dont think the client would be pleased getting an electrician as well as yourself for no reason.meggar technique is the best way to fault find.

[Kp3]

it has got to be something to do with start delay or the heaters because if it runs while ur there then trips when you've gone it wont show up on a meggar unless you meggar the heaters. what type of delay timer is on the cabinet?

[philfridge]

it has got to be something to do with start delay or the heaters because if it runs while ur there then trips when you've gone it wont show up on a meggar unless you meggar the heaters. what type of delay timer is on the cabinet?

The electrical fault will show up on a megger regardless as neutrals are joined. So only mains plug needs to be tested with the megger to indicate a fault. Only then if a suspect Reading is given will components need to be checked.

[Kp3]

i never do that as i think there will be controller fitted to it so i dont fry the board. each to there own way

[lowcool]

kp3 youll only fry the controller by meggaring the probe inputs.maybe read the instructions that came with the meggar.as you say everyone to their own but payment for job would be in the bank by now