Copeland scroll not engaging

[fridgey]

I've just been attempting to commission a R410A ducted 33 kw ducted split system for a warehouse office. The compressor is a copeland scroll when the compressor starts up and the motor runs but the scroll dosen't engage.

This of course it is one of these stupid copeland scrolls with that annoying high discharge temp safety discs. I understand the reseoning behind them putting it in as a protection.

But surely on a brand new compressor on a brand new unit it should not cause a problem. Anyway rang the manufactuer of the Unit. You know what they told me, hit the top of the compressor with a mallet to reposition the disc.

Is this a common problem? Has anyone has a similar expierience?

I have yet to try the suggest remedy i'll let you know how I go.

[coolhibby1875]

i normally swap the phases round and run for 10 secs normally does the trick!

[goshen]

i normally swap the phases round and run for 10 secs normally does the trick!

that is 100% correct!!!!!!!!!!!!
works for me to!

[Goober]

Yep, had the exact same problem, brand new unit compressor starts but does not pump, we changed the compressor, and sent the faulty one back to the supplier, in this case Temperzone in NZ. Unfortunatley the compressor worked on their test bench so they wouldn't cover it. We got it back put it into a second hand unit and test ran it...same thing not pumping, reversed the phases and ran it then put them back and it started pumping, but can we use that compressor again..don't think so..and Temperzone got the sale of another compressor.

[fridgey]

Haven't been back yet to look at it. Reversing the phases was the first thing I tried with no sucess, so it doesn't always work.

Goober ironically this unit is a temperzone as well. Maybe this says something!

I certantly don't want to get stuck with a compressor i can't use. If I cant get it to work i'll definatley be getting there rep out to gaurantee me warranty, before I think of replacing it.

[sendhilkmar]

If it is a Safety device (ASTP) activating to avoid the compressor failure then you need to find out the root cause. I have experienced this problem at least 4# units and every where I found restriction in the low side like TXV chocking or less refrigerant charge and Low LP set point. After correcting this all those sites were running till now without any problem.

[oldesky]

Fridgey, If the ASTP has tripped you may need to wait for around 2 hours for it to reset. A common reason for the trip on start up is low charge causing high discharge temps. Try bomb charging the high side (preferably with the correct charge) before start up.