Seized Scrolls

[jwasir]

Hi,

From past some time, we are getting some seized scrolls. These are ZR types from Copeland w/o oil sight glass.

After replacing the compressor, no unsual parameters were noticed. The suction, discharge, SH, subcooling, etc all are within the envelope.

I wonder what happens during night, which causes low lubricant and seizes the compressor.

Any thoughts and ideas!!

[goshen]

Hi,

From past some time, we are getting some seized scrolls. These are ZR types from Copeland w/o oil sight glass.

After replacing the compressor, no unsual parameters were noticed. The suction, discharge, SH, subcooling, etc all are within the envelope.

I wonder what happens during night, which causes low lubricant and seizes the compressor.

Any thoughts and ideas!!

hi check head pressure control causes liquid to return in suction line and oil diilution and migration
also check sump heater usualy wrapped arround compressor
a scroll can handle liquid slugging( not for long periodes ) but cant handle no oil
:cool:

[jwasir]

Thanks Goshen,

There is fan cycling controls on the system but mostly they fail in summers, when Head pressure is within the range.

All the comp's are equipped with crank case heaters.

I cant understand what is causing NO OIL conditions?

[Gary]

So far, all we know about this system is that it has a scroll compressor. For all we know it could be anything from a cascade freezer to a heat pump to a process system to whatever. It could be TXV or cap tube or fixed orifice or low side float or whatever. It could use any of the multitudes of refrigerants out there along with any of the many types of oil. It could have infinite variations of control strategies... or maybe it just plugs into the wall.

We can't see it from here. All we can see is your description and you haven't even begun to describe it.