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SECTION 3 INSTALLATION
Pressure Adjustment Screw
3.6 Delivery Pressure Adjustment
Delivery pressure is controlled by the relief valve mounted next to the pump in the tank compartment. Turn-
ing the pressure adjustment screw clockwise increases pressure on the spring and raises the delivery pressure.
Turning it counterclockwise reduces pressure on the spring and reduces the delivery pressure. The pressure is
adjusted at the factory to deliver about 175 psig (12 bar) at 1.5 gallons per minute (5.7 l/min). This is an appropri-
ate setting for the PT-36 on an M3 system. Ordinarily, this should not require further adjustment.
This relief valve sends bypassed coolant through the IGBT cold plate and back into the tank. Consequently, a
closed discharge line should not damage the pump.
The pump also has a relief valve built in. This valve is set to be fully open at 225 psig (15.5 bar) by the pump
manufacturer. Its sole purpose is to protect the pump should the external relief valve fail closed. This relief valve
should not be adjusted in the eld.
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