Zr 190 kc scroll compressor not running for long time

[mbc]

Hi

3 days ago i done work with Copland scroll compressor ZR 190 KC made in Thailand
R= 22
It is running well for about 20 Minutes
and then with out changing any item compressor is running with out doing compress
I know it has system when liquid come to compressor up side goes up and does not compress
but here we have not any liquid in suction line3-
zaa.jpgzaaa.jpg
Also on compressor they wort it can happen

compressor has heater i cover it because it is in cool area

suction = 45-50 PSI we have KVL and suction separator

discharge = 180 - 200 PSI

current 21 A

I poll it out and changed with maneurop compressor it works well

Thanks

[joe-ice]

The internal relief valve lifts when there is 28 bar difference between suction and discharge pressures regardless of whether there is liquid there or not .

[mbc]

Hi
but here we have about 10 bar difference between them.

[joe-ice]

Ya i noticed that but is it 10 bar under all working conditions also the pressure relief is a one off safety with no guarantee it will work or reseal after its first fired. Is there a high pressure safety on the system with a manual reset as it would be highly unlikely the compressor would reach the trigger differential if there was . Only other thing i can think of is if the compressor is getting reversed mechanically or electrically while in operation which would not affect a piston maneurop

[mbc]

Hi
Yes we have safety valve and high pressure control

[monkey spanners]

I believe there is also a valve that opens if the scroll gets too hot that will stop the compressor pumping.

[sendhilkmar]

This is the safety valve(ASTP ) that opens when scroll gets overheated. If this happen then the compressor runs without pumping as the scroll sets separated internally. many at times this happens due to very low suction pressure (less than 15 psig). This compressor is not failed ; this problem can be resolved once you correct the system pressures /temperatures

[mbc]

Hi
What is the reason of that
I tried 3 day
No high temprether
No high pressure
Suction pressure is stayable
I told to copland Co l had picture and film of that
Unil now they did not answer
I had discussion with them and I found they have same case in this type