TM 5-4520-253-13
Table 3-3. Unit Maintenance Troubleshooting – Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
f.
g.
h.
i.
Disconnect red and brown wires from flame switch (9). Using volt ohmmeter,
place one probe against each terminal of flame switch (9). Meter should
indicate infinite resistance.
Heat bottom of flame switch (9) to 130°F (54°C) and place probes on
terminals. Switch should snap (close) and meter should indicate zero
resistance.
Connect red and brown wires to flame switch (9).
Install flame switch and bracket assembly (6) in opening (7) and attach to
heater bulkhead using two screws (4) and lock washers (5). With screws
loosened, adjust flame switch and bracket assembly downward as far as it
will go. This seats the flame switches (8 and 9) against the heat exchanger.
Tighten screws (4).
If either flame switch (8 or 9) is defective, replace flame switch and
bracket assembly (6).
Change 2
3-35
