Why scroll compressor is not pumping

HailWV liked this post. Originally Posted by knave. Join Date Nov Location St. Never had an issue pumping down a scroll; just leave enough positive pressure in it to keep you out of the green.

The scrolls rattle a bit as you near the end. Open the electrical panel so you can push in the contactor if it has a low pressure switch. The Internal Pressure Relief valve should not open unless the pressure differential becomes quite great - on the order of or more psi on Copelands, if I recall correctly.

If it opens during a pump down, it is far too weak and failed. Is the Religious Right to blame for Christianity's decline? They argued that, as the Religious Right became increasingly visible and militant, it became associated with Christianity itself. Some manufacturers are using small diameter condenser tubing which makes pump down very difficult if not entirely impossible.

I would caution about partial pump downs on RA systems. Since its an azeotropic mix you never know in what relation you actually pumped down each component. Same is valid for leaks. Therefore I alway recover entirely and never have an issue. I would also caution on pushing in a contactor. Seen three blow up over the past five years. All , so maybe okay on a resi thread. Yoo can pump a scroll down. Dont pump it into a vacuum. Some scrolls have another internal protector that works off compression ratio.

Originally Posted by Hvac talker. I will also add this info. You need to have your high side gauge hooked up. If you go off on high head before you get pumped down ,your condenser may not be big enough to hold the complete charge. This is not usually a problem with a line set run of 25 feet or less. This subsequently disengages the scroll but the compressor motor stays running unloaded until the compressor cools, then in re-engages automatically.

So it seems like there is another problem with your display fridge, possibly short of gas or faulty TEV. You didn't mention what refrigerant? Re: Coopeland Scrol not pumping. Re: Coopeland Scrol not pumping My money would be on a short power cut and the power came back on as the compressor was spinning backwards and it kept going that way. It is also worth fitting a time delay of a minute or so in the control ciruit just before the contactor coil connection, to stop this being able to happen.

Something else to check is the differential on the LP switch sometimes if its set too low or has gone out of adjustment they can cut out on LP and be running backwards as the LP switch cuts back in and they stay running that way. Cheers Jon. Re: Coopeland Scrol not pumping if a scroll wheather it single or 3 phase runs the wrong way you would know about it as it would be jumping about the unit and making one almighty noise i think the scroll has just been diengaged due to faulty start capacitor.

Originally Posted by monkey spanners. My money would be on a short power cut and the power came back on as the compressor was spinning backwards and it kept going that way. Re: Coopeland Scrol not pumping Thanks all for your thoughts on the subject, I did check the refrigerant charge R22 , the sight glass cleared quite soon so I think its not short of gas. Ill check the capacitors and LP switch as recomended. I let you all know how I get on. Many thanks again.

I disagree with you and fridgey. Earlier models that had this would trip the thermal protector of the motor because the discharge was directed to it.

Modern scrolls don't do this because they just release the pressure of the floating seal and do not bypass discharge to suction. If motor was running the bymetal would not reset by just turning of the power off and back on. It simply would not cool enough. I can confirm this if fridgability mentions the model and serial number of the compressor to check manufacturing date. Came across a brand new one just last week with the bimetal dome open ,the compressor was running and no pumping the LP was set to low it had no suction cooling and the dome opened, just left the CFM running to cool it down with the compressor disconected , it cooled down within hour or so , then tested it and corrected the LP settings.

It would possibly have been cycling on klixon before i got there. Originally Posted by fridgey. What I've said above is correct, bar the fact that it auto reset itself. The compressor does have to be turned off too cool. I was going from memory and it's been a while since i've come across the situation. The cause of the compressor disengaging in both instances was a system related problem.

Was the system was short of refrigerant Was due to the system having poor suction superheat, due to a system design issue. In both case it was not a fault of the compressor. I said I don't agree, not that I hold the flame of truth! Give me the model and if it is a small one like fridgability mentioned maybe the serial number too and we'll start a new thread on this one!

Re: Coopeland Scrol not pumping I had a similar experience on my system. Thread: compressor running, not pumping. Thread Tools Show Printable Version. I never saw this before. I will help you, just so you dont talk bad about me What were your amps. Originally Posted by wolfstrike. I did 3 repairs on a commercial property. I didn't measure amps because I figured the outcome would be the same, compressor is bad. I don't normally work on commercial property. Motor spinning backwards, open relief, broken crank, or advances temperature relief wont reset.

If it ran low on gas. The temperature device may have opened and wont reset. High and low sides on your gauges open?