Card Set Information
Relief Valves Fire Engines
FD Relief Valves intake and discharge
Discharge Pressure Relief Valve Def:
Handles sudden changes of discharge pressure by re-routing to the intake side of the pump.
Discharge Relief features
Operating pressure range of 75-300 PSI
Greater than 300 PSI needs to be set OFF
In OFF position when not in use
Exercise and reset weekly or after use to 150 PSI
Discharge Relief Reset Procedures
Raise engine to discharge pressure
Turn valve to ON
Turn T valve counter clockwise until valve opens (Amber)
Then turn T valve clockwise until valve closes (Green)
When no longer needed reduce RPM to close valve and then reset to 150.
Pressure Sensor Governor (PSG)
Not a true relief valve.
Reduces engine RPM to reduce pressure
Intake Relief Valves (Dump Valves)
Externally mounted- set to 100 PSI to protect against water hammer from intake, protects hose and from cavitation
Factory installed- pre-plummed and dumps to ground
Intake Relief Valve setting
Shall be set every 30 days or after pumping
Charge and intake line from hydrant
Back off lock nut until water flows
Slowly tighten until water stops flowing, then 1/4-1/2 farther
Tighten the lock nut.