Fellow Users, Does anyone know the thread size of the vent plug on the HT or LT cooling water pumps? We will be draining our cooling water systems soon and would like to add vent valves at these locations, but do not know if this is NPT, British Pipe Thread, Metric, or ?? and would like to have parts on hand when the system is drained.
Follow-up: The HT and LT water pump vent plug thread size is R 1/4″. We added vent valves to these locations during the 500hr maintenance on our 4 W50SG units, but still experience multiple trips on lo LT and HT pump pressure after refilling and restarting the units. The best solution we’ve found thus far is to extend the trip delay timer and hold the unit at min. load for half an hour or so, until most of the air has been vented from the system.
Following up this conversation you might want to try to vent on your highest point which in our case is at the radiators, we use the vent valves at the radiators to vent air in the system plus the vents after the preheater pumps. The operators also circulate the water and vent before start the engines.