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jdunc2301
12-09-2016, 08:39 PM
Hi

I've got a job driving me mad atm.

Single phase Copeland scroll, compressor starts and runs for a short period and then turns off (internal o/load) C-R open circuit.

I have checked the wiring against our diagram below on the soft start PCB and It is correct.

When the compressor was running before it cut off I noted the run current as approx:
Run connection-2~
Start connection to cap-11~
Contactor to common- 8~

I disconnected the start capacitor once the comp was running and the compressor kept going with no problems.

The run connection current went up to 10~ and the pot seemed much smoother.

I'm guessing the soft start PCB isn't switching the start winding out? Any thoughts would be appreciated as it seems to be happening on two identical units!!





14318

chemi-cool
12-09-2016, 08:55 PM
Why use a soft start on a single phase compressor? It's already got a start circuit and a start capacitor.

nike123
12-09-2016, 08:57 PM
Start capacitor should be switched off at 0.5 to max 2 seconds after start. It is not capable to work longer than that! What is make and model of soft starer? And, as Chemi pointed out, if you use soft starter on single phase unit, than it can affect starting torque of compressor in such way that is not capable of overcoming internal mechanical resistance and cause stalling!

jdunc2301
12-09-2016, 09:04 PM
Its not a recognizable model of soft start.

Its domestic heat pump perhaps to stop lights dimming.

Would I be able to wire it direct on and do without the PCB? Wiring diagram?

nike123
12-09-2016, 09:11 PM
Of course you can! You need original starting group of compressor in question! What is compressor make and model?

jdunc2301
12-09-2016, 09:19 PM
Its a Copeland ZP23K3E-PFJ-522, run capacitor 60uf start cap 100uf

Im guessing the reason why im having this problem is because the start winding is still "engaged"

Thanks

nike123
12-09-2016, 09:37 PM
You should use correcct soft starter; http://www.actrol.com.au/global/assets/howto/323-emerson-css-series_soft_starter_operating-instructions.pdf

jdunc2301
12-09-2016, 09:42 PM
I'll take a look. Thanks

If both the start and run capacitors were still in circuit would I see this sort of thing?

monkey spanners
13-09-2016, 09:45 AM
If you can put your amp meter round the start capacitor wire you should see an initial peak then drop to nothing as the capacitor is disconnected by the start relay, if the current doesn't stop either the start relay is faulty (welded contacts or such) or the compressor is not starting properly either due to faulty compressor or supply voltage issues.

chemi-cool
13-09-2016, 05:08 PM
The compressor has its starting relay and doe's automatically and a soft start will kill it.

jdunc2301
19-09-2016, 06:08 PM
I finally found the fault. The start capacitor 100uf and run cap 60uf had been swapped over.

Swapping them back over solved the issue.

Glad I found it as it would have eventually burnt the winding out