Discharge Valve Maintenance


Discharge Valve Maintenance

Fire trucks today are built with many complex systems. Those systems all require some general maintenance to keep the front line truck ready. One of those components at the heart of the truck is the fire pump. The fire pump is no exception when it comes to some basic maintenance.

How many of you have pulled on a valve and found it difficult to open or close? Was it one of those valves on your truck that you just don’t use all that often?

Now that you manage to get it to open, then closed again, it leaks right? Maybe it’s a valve you use all the time and you’ve noticed when the pump is in gear, and that valve is closed, you have a pressure reading on the gauge. It’s likely that valve is leaking and pressure is building up behind the cap.

Whether you flow large amounts of water from a city hydrant system, or drafting out of a lake, pond, or dry hydrant, the water may contain dirt, sediment, and other debris. This debris is not just flowing through the impellers and valves we have open, it is also reaching the piping and areas of the pump that you are not currently using. Over time, this debris starts to build up and settle in our valves, making them difficult to open and subject to damage due in part to sand and other abrasives scoring the ball and seal surfaces.

What we need to do is some basic maintenance to these valves. Remember most things tend to fail due to lack of use, not too much use. The procedure explained below will take about (10) ten minutes after a pumping drill and should be done about once per month.

Before performing this procedure, be sure your truck is not in “pump” mode.

Open the Tank to Pump Valve. This will allow tank water head pressure into the pump allowing us to open our discharge valves without the need to disconnect our hoses.

With tank head pressure inside the pump, open each individual discharge valve drain. Initially you may see dirty or off-color water drain out. When the water begins to run clear, operate the discharge valve to the full open and full closed positions several times. This will “lubricate” the valve with fresh clean water and will help to keep your valve opening and closing smoothly.

Although we have been talking discharge valves, the one valve that seems to be forgotten is the master pump drain valve. This valve is located at the lowest point in the pump house and is where most of the dirt and debris settles. Now is a good time to open this valve and let the water run clean as well. Once clean water is draining, exercise this valve a few times as well. This will lubricate the sealing rings inside the valve and lessen the chance that you will need to put your feet on the diamond plate to open it.

Now that all discharge valves have been drained, exercised, and the master drain has been opened and exercised, continue to perform other pump tests as needed. Close the Tank to Pump Valve and put the truck back in service.

If you have any questions regarding this information or need any assistance, please contact us at: 
Telephone: 651-450-5200
Fax: 800-488-1228