Test Setup For Fuel Regulator And Shutoff Valve; Fuel Regulator And Shutoff Valve Maintenance - Piper Navajo Chieftain PA-31-350 Service Manual

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REGULATOR
Figure 13-13. Test Setup for Fuel Regulator and Shutoff Valve
13-34. FUEL REGULATOR ANDSHUTOFFVALVE. (RefertoFigure 13-13.) Thisunitprovidespreset,
regulated fuel pressure as well as remote shutoff to the heater. It is set for 7.5 psi. The shutoff valve is operated
by a solenoid.
a. Removal of Fuel Regulator and Shutoff Valve.
1. Disconnect the electrical leads from the valve.
2. Disconnect the fuel lines from the inlet and outlet openings. Take note of these connections
for correct installation.
3. Disconnect the screws attaching the unit to its mounting bracket.
b. Adjustment. The fuel regulator and shutoff valve used in this system are adjustable but not
repairable. The following steps cover the proper adjustment of this unit:
1. Install the regulator in a test stand similar to that shown in Figure 13-13.
2.
Install a 2.5 gph nozzle (Janitrol Part No. D08D09). Stoddard solvent should be used for,
testing.
3. Apply a fluid pressure of 20 to 50 psi and energize the solenoid.
4. Using a screwdriver, break the adjustment seal and adjust the regulated outlet pressure as
close to 7.5 psi as possible. (Turn clockwise to increase pressure; counterclockwise to decrease pressure.)
5. Slowly vary the inlet pressure from 10 to 50 psi. The outlet pressure should remain between
7.0 and 8.0 psi.
6. With the inlet pressure of 50 3 psi, de-energize and energize the solenoid at least twice.
The outlet pressure should be 7.0 to 8.0 psi with the solenoid energized. When the solenoid is de-energized,
the pressure should drop to zero and the fuel flow from the nozzle should stop.
7. With the solenoid energized, slowly reduce the inlet pressure from 50 to 10 psi. Outlet
pressure should remain between 7.0 and 8.0 psi.
8. During the above test, observe for signs of external leakage. Any leakage is cause for
rejection of the regulator. After satisfactory adjustment has been made, apply Glyptol around the threads
of the adjustment screw and in the slot.
c. Installation of Fuel Regulator and Shutoff Valve.
1. Install the fuel regulator and shutoff valve on its mounting with the attaching screws.
2. Connect the fuel lines to the inlet and outlet openings and secure.
3. Connect the electrical lead. Be sure to slide an insulating sleeve (or tape) over the
connection to avoid a short circuit and tie the sleeve in place.
Revised: 2/8/82 HEATING AND VENTILATING SYSTEM
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NAVAJO CHIEFTAIN SERVICE MANUAL