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IOM
Figure 1: Relief Valve Typical Installation
4.
Operation
The FP-3HC-0 Pressure Relief valve is held closed by the force of the spring above the diaphragm attached to the closure disc.
The inlet pressure is sensed by the diaphragm, when the inlet pressure force applied under the diaphragm exceeds the adjusted spring
force, the valve will open to relieve any overpressure.
When the inlet pressure force drops to below the force of the spring the valve will return to close.
4.1
Re-adjustment
Tools required: adjustable wrench
The valve is pre-set before leaving the factory, the set point is clearly indicated on the setting sticker on the valve cover.
If the set point is to be adjusted follow the instructions below:
4.1.1
Unscrew the tamper proof cap (item 23, fig.2) exposing the adjusting screw and loosen the locknut (item 19, fig. 2)
By alternately turning the adjusting screw (item 18, fig.2) a half turn and then reading the outlet pressure, gradually adjust
the pressure: Counter-clockwise to decrease (-) the inlet pressure or Clockwise to Increase (+) the inlet pressure.
4.1.2
If needed replace the setting indication sticker to display the new setting value.
4.1.3
The pressure has been set re-tighten the locknut and replace the tamper proof cap.
FP-3HC-0
Relief Valve
Fire Pump Casing Relief Valve Installation
Pressure Relief Downstream of Pressure Control / Reducing Valve
FP-3HC-0
Relief Valve