HomeMy WebLinkAbout303.004 - Pressure Control Valves
Effective Date: October 2007 Robert J. Garcia, Engineer
Current Revision Date: 05/27/2025 Section 303.004
Next Revision (1) Date: 05/27/2027 Page 1 of 3
Fresno City Fire Department
300 Training and Equipment Manual
SECTION 303.004 PRESSURE CONTOL VALVES
PURPOSE
To inform members how to set and test Fresno Fire Department (FFD or Department)
Pressure Control Valves known as “Relief Valves” on equipped apparatus.
APPLICATION
There are only two items that control pressure on hose lines: the throttle and the
discharge gates. The relief valve is a very important safety feature, which protects
those working on or around hose lines from over pressurization.
NFPA 1901, Standard for Automotive Fire Apparatus, 2016 edition requires a pressure
relief device be part of any fire apparatus pumping system. The device must operate
within 3 to 10 seconds after discharge pressure rises and must not allow the pressure
to exceed 30 psi above sea level.
When at a working fire, the relief valve should remain off and momentarily turn
on/open/amber. When additional pressure occurs from shutting down another line for
advancing, or from pressure differentials in the domestic systems or supply lines, the
relief valve should momentarily open if the set pressure is reached.
OPERATIONAL POLICY
To standardize and ensure the proper setting and operation of relief valves at fire-
ground emergencies, a weekly test of relief valves will be conducted at the station
each Sunday.
OPERATIONAL GUIDELINE
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Effective Date: October 2007 Robert J. Garcia, Engineer
Current Revision Date: 05/27/2025 Section 303.004
Next Revision (1) Date: 05/27/2027 Page 2 of 3
PROCESS
Setting the Relief Valve
1. To set the relief valve, bring the pump up to the desired operating
pressure using the discharge pressure gauge.
2. Slowly turn the hand wheel counterclockwise until the relief valve
opens and the amber pilot light is lit.
3. Turn the wheel clockwise slightly until the light is out. The relief valve
will now operate at set pressure and is set slightly higher than the
discharge pressure.
4. When the pump is not in operation, the adjusting hand wheel should
be turned clockwise so the control is set slightly above the normal
operating pressure for hotlines. When the pump is put back into
operation, reset the relief valve.
Weekly Relief Valve Testing Procedure
1. Turn the control valve adjusting hand wheel clockwise as far as
possible, thus “locking out” the control valve.
2. Bring the pump pressure up to 183 psi and turn the handwheel
counterclockwise until the relief valve opens.
3. Turning the control valve handle in and out with a pump pressure of
183 psi will cause the relief valve and control to operate. This working
action frees the valve and helps to ensure proper operation.
Caution: Do not operate the pump for a prolonged period during the
test, as damage to the pump may occur.
Auxiliary Pump Relief Valves
The auxiliary pump relief valve maximum pressure is set at 250 psi. Some models of
apparatus will require two (2) members to set the relief valve, as there is no external
throttle on the pump panel.
Setting the Auxiliary Pump Relief Valve
Effective Date: October 2007 Robert J. Garcia, Engineer
Current Revision Date: 05/27/2025 Section 303.004
Next Revision (1) Date: 05/27/2027 Page 3 of 3
1. To set the relief valve, bring the pump up to the desired operating
pressure of 250 psi using the discharge pressure gauge located on
either the pump panel or in the cab.
2. Slowly turn the hand wheel counterclockwise until the relief valve
opens and the amber light is lit.
3. Turn the wheel clockwise slightly until the light is out. The relief valve
will now operate at set pressure.
4. When the pump is not in operation, the adjusting hand wheel is already
set to a maximum pressure of 250 psi.
INFORMATION
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DEFINITIONS
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CROSS-REFERENCES
NFPA 1901, Standard for Automotive Fire Apparatus, 2016 edition.