Thermostatic Valve – why is it needed?

Questions & AnswersCategory: GeneralThermostatic Valve – why is it needed?
Guest Staff asked 2 years ago

Why thermostatic valve is required? What happen if we removed that vale from system?

3 Answers
Cas Staff answered 2 years ago


The valve is needed for when the compressor is still cold (after stop) or when it is running in very cold conditions (winter).

When the compressor oil is cold, the valve is bypasses the oil cooler so no oil flows through the cooler. This is done to heat up the oil as soon as possible to remove water condensate.

Low temperatures are the number 1 enemy of screw compressors. The compressor needs to heat up quickly to remove any water condensate as quickly as possible.

If you remove it, one of two things will happen: all oil will flow through the oil cooler. Or no oil flows through the oil cooler at all. Probably the second thing will happen as it’s the path of least resistance.

If you’re in India and it’s very hot and the compressor is running all the time, than basically this thermostatic valve isn’t doing much.

aziz ahamed answered 3 months ago

thermostatic valve required as all oil circulating nicely. and oil cooling perfectly, oil divided two way to circulate, one way through oil cooler , other way return directly, so oil have a chance to cool

Jason Tiden answered 4 weeks ago


I’m having problems with a ingersoll rand compressor(SE90-160kw) single stage compressor which is not running when start-up and giving CK MOTOR ROTATION fault on the display unit.

The unit has been running and delivering air for a year, but due to several power outage we had this problem.

I checked the display unit and got discharge package at 100 psi that’s from 2 same units running, airend temperature at 66 degree celcius, sump pressure 0 psi and there is 3 psi in the separator which I think should have around 29 psi. 

I am not too sure if this can still give the rotation fault and if I need to pressurize the separator how can I go about doing it? Or is there anything else I missed.

Thank you.


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