SECTION 3
INSTALLATION
3.4
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 PT36 on an M3 system . Ordinarily, this should not require further adjustment unless the CC11
is used in a different application .
This relief valve sends bypassed coolant through the radiators 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 250 psig (17 .3 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 field. In the unlikely event that the external relief valve fails closed and the
discharge line is closed, a thermostat will stop the pump motor if the pump temperature goes over 131° F (55° C) .
Pressure Adjustment Screw
66