Cryo Refrigeration Help

[Gary]

235psig - 108F
240psig - 110F
250psig - 113F

These settings are not high enough for a warm day, much less a hot day. I would expect a high pressure cut-out to be set up in the neighborhood of 130-135F or even a little higher.

And the pressure drop across the condenser is still puzzling. Are there any other devices between the two pressure measurement points?

[Cryo99]

These settings are not high enough for a warm day, much less a hot day. I would expect a high pressure cut-out to be set up in the neighborhood of 130-135F or even a little higher.

And the pressure drop across the condenser is still puzzling. Are there any other devices between the two pressure measurement points?

Unfortunately, 130F corresponds to a pressure of 305psig, which is above our system RV setpoint. My guess this is the downside of the refrigerant change they did many years ago.

Still, the system worked last year with these same settings and during days of hotter weather than this. Could the explaination be that the condenser performance isn't horrible, but not as good as it was last year?

Other than the oil seperator there isn't anything in the line between the two points besides pipe and the condenser. The gauge on the outlet of the oil sep is about 2-3psi lower than the compressor discharge P.

[Gary]

Unfortunately, 130F corresponds to a pressure of 305psig, which is above our system RV setpoint. My guess this is the downside of the refrigerant change they did many years ago.

Still, the system worked last year with these same settings and during days of hotter weather than this. Could the explaination be that the condenser performance isn't horrible, but not as good as it was last year?

Other than the oil seperator there isn't anything in the line between the two points besides pipe and the condenser. The gauge on the outlet of the oil sep is about 2-3psi lower than the compressor discharge P.

I'm thinking there may be a restriction in the oil separator, possibly a plugged inlet screen if it has one... and if that restriction appeared recently that would explain why it worked better last year.

I'm guessing the pressure control is sensing the higher of the two pressures?

Is the RV on the condenser? If so, we could see a big improvement by moving the pressure sensing connection to the condenser out port.

But that does not resolve the restriction issue. You might want to contact the oil separator manufacturer to find out what their normal pressure drop should be.

[Gary]

The gauge on the outlet of the oil sep is about 2-3psi lower than the compressor discharge P.

Hmmmm... then the drop is in the condenser. Maybe I'm wrong on this, but it seems like an excessive pressure drop for a condenser.