Table 4-2. Organizational Maintenance Troubleshooting - Continued
TESTING OR INSPECTION
4 - Continued
Disconnect power plug. Disconnect wires at flame switch, (8, fig. 4-5). It is normally possible to
remove the flame switch without removing the carburetor or burner head. Remove screws (1),
washers (2 and 3) and pull out assembled switch and bracket (4 through 8). Remove screws (4)
and washers (5 and 6) securing flame switch (8) to mounting base (7). Pull off defective switch.
No repair is possible. Install a new switch by reversing the removal procedure. Make sure tip of
switch probe engages bracket on heat exchanger.
Step 13. Check for power to solenoid valve. Open access doors. With power plug connected to heater and
room thermostat set above ambient temperature, turn on heater. Check for 24 VDC at electrical
connector which supplies power to solenoid valve.
Fuel pump power supply was check per step 6. Turn off power and disconnect power plug.
Check continuity at electrical connector between power supply and fuel pump power supply and
solenoid valve. Tighten loose connections.
Step 14. Check solenoid coil. Remove hex nut at terminal on solenoid valve. Pull off wire and remove
solenoid coil. Check for continuity between solenoid wires.
If coil is open, replace solenoid valve. Using open end wrench, unscrew and remove solenoid
stem. Discard old solenoid coil, stem, and related parts. Install stem and preformed packing
from new solenoid valve into carburetor body. Install washer and solenoid coil, and connect
leads at solenoid terminal. Secure with hex nut.