Chicago Pneumatic QRS Thermal Valve and Minimum Pressure Check Valve Kit - 2901109500
This kit contains the parts needed to rebuild both the thermal valve and minimum pressure check valve (MPCV) assembly.
A compressor thermal valve opens when the oil gets hot to let coolant/oil flow through the cooler before the oil is sent back into the sump tank. This prevents the compressor from overheating. If your compressor is consistently shutting down on high temp and your oil is full, more than likely this valve needs to be replaced. It is recommended to replace the thermal valve every two years or 8,000 hours of operation.
The minimum pressure check valve keeps air pressure inside of the sump during the initial startup of the compressor. This helps the oil circulate throughout the compressor on start-up. Once the pressure inside of the oil sump reaches approximately 60psi, the valve will open and let compressed air flow downstream. A properly functioning MPCV will prevent oil carryover into your piping system. This will also prevent high pressure air from your receiver and air piping from re-entering internal compressor components. If air is leaking from the inlet after the compressor has been shut off for a period of time, there is a good chance that this valve failed and is letting high pressure air flow back inside of the compressor.
2901109500 is an OEM part. Sometimes this is displayed in a parts manual as 2901-1095-00 or 2901 1095 00. The 2901109500 thermal valve and MPCV kit was used on most of the Chicago Pneumatic QRS3.0 through QRS15 compressors. This was also work on several of the Quincy QGS series of rotary screw compressors, NAPA rotary screw, and several of the Atlas Copco G and GX series air compressors. Please contact our parts department if you would like confirmation that this part will work with your air compressor.