- Question Title: Quincy QSI-370 over temperature
- Asked by: Guest
- Asked On:
- Answers: 1
We are having problems with the compressor shutting down for over temp.
the combination after cooler is hot on the inlet sides of the oil lines and for the air inlet. and warm on the outlet sides.
for example the air inlet is 175 degrees F (=80 degrees Celsius) the outlet was 75 degrees F ( =24 degrees Celisus).
The oil inlet was 44 degrees cooler on the outlet VS the inlet side.
In my mind the the combo cooler is bad, but I'm not sure if there is any other valves etc. that could effect this.
any input would be great.
Answers & Replies
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Hi,
The values you post sound good... I think the cooler is ok. I suppose you checked the obvious things, like how dirty/clean the cooler is.
But temperatures alone don't tell the complete story. It is depended on the flow.
A cooler is a heat exchanger. Heat from the oil is transfered to the cooling air. The heat flow is expressed in kW and can be calculated. Also, the temperature drop of the oil to be cooled can be calculated.
The temperature drop depends on the specific heat of the oil, the density, and the flow rate.
To make a long story short:
The temperature of the oil is controlled by a thermostatic valve. It usually opens around 60 degrees and will be fully open around 80 degrees.
In your case, it could be that the thermostatic valve doesn't open completely... only a small amount of oil flows through the cooler, the rest is by-passed. This valve is usually found near the oil filter.
I have attached a picture of how such a valve looks like and a drawing of the oil system of a compressor (both from a different compressor, I don't have this information for your specific make/model).
I have tried to make my story clear with arrows and temperatures. Thick arrows is big flow, skinny arrows is small flow.
Good luck and I love to know when you solved the problem.
Cas.