Taking Care of Your Discharge Relief Valve


Taking Care of Your Discharge Relief Valve

The discharge relief valve system is one of the most important safety features on your Waterous fire pump. The relief valve is designed to keep dangerous pressure surges from injuring firefighters on hoselines. The system consists of two components: the pilot valve, which is mounted to the pump panel; and the relief valve, which is mounted between the pump intake and discharge fittings. The pilot valve manages the system by sensing discharge pressure and controls the opening and closing of the relief valve. The relief valve directs water from the discharge of the pump back into the intake of the pump when pressure surges occur.

Do you have a discharge relief valve that is sluggish or seems to stick open or closed? Chances are the relief valve is not worn out, it actually hasn’t been used enough. Just like the human body, a relief valve needs to be exercised in order to stay in good shape. It doesn’t take a lot of time. In about ten minutes per month, you can perform some easy exercises that will help keep your relief valve system working and keep your firefighters safe.

Just follow these simple steps:

  • Engage the pump, begin circulating water, and increase pump discharge pressure to 150 PSI.
  • With the pilot valve OFF, remove the strainer assembly. Then clean the strainer and the orifice in the end of the strainer rod.
  • Turn the pilot valve ON and OFF several times. Water should flow from the opening in the ON position and stop in the OFF position.
  • Check the strainer o-rings and replace if damaged.
  • With the pilot valve in the OFF position, replace the strainer assembly (finger tight only).
  • With the pilot valve OFF, turn the large pilot valve handle counterclockwise until it stops.
  • Slowly turn the pilot valve ON. The relief valve should open (amber light) and pump discharge pressure should drop below 90 PSI.
  • Slowly turn the pilot valve OFF. The valve should close (green light) and pump discharge pressure should rise back to 150 PSI. Repeat steps 7 and 8 until the system responds quickly when turned ON and OFF.
  • Reset the pilot valve to the desired setting and decrease engine speed to idle.

Something else that you can do to help keep your relief valve and other pump systems operating well is to drain the pump and flush it with clean water once a month. This will help flush deposits of sand or other foreign materials out of the pump and help prevent the premature failure of moving parts and seals. By performing some very simple maintenance on a monthly basis, you can see how easy it is to keep your Waterous fire pump and accessories running like a well-trained athlete.

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