TM 10-4520-259-13&P
SECTION IV. UNIT TROUBLESHOOTING PROCEDURES
4-9.
GENERAL.
This section contains procedures to isolate water heater defects that can be corrected by unit maintenance.
Perform the checks and corrective actions in the order listed.
4-10.
GENERAL INSTRUCTIONS.
The symptom index lists the common malfunctions which may be found during water heater operation. Use this
index for quick access to the troubleshooting procedures in Table 4-2. This manual can not list all possible
malfunctions that may occur, nor all tests or inspections and corrective actions. If a malfunction is not listed or
is not corrected by listed corrective actions, notify your supervisor.
4-11.
TROUBLESHOOTING.
MALFUNCTION INDEX
Troubleshooting
Procedure
EXHAUST SYSTEM
Exhaust gas from smoke stack (M-80) or exhaust duct (M-85) is smoky............................................. 10
FUEL SYSTEM
Fuel pressure gage indicates pressure too high or too low.................................................................... 3
Fuel pump leaks................................................................................................................................... 6
Fuel pump fails to deliver fuel to burner ............................................................................................... 7
Noisy fuel pump .................................................................................................................................. 4
Pressure gage indicates pulsating pressure.......................................................................................... 5
WATER HEATER
Blower and fuel pump motor are noisy............................................................................................... 13
Blower motor contactor continues to trip .............................................................................................. 9
Burner fails to ignite or ignition is delayed............................................................................................ 8
Flame failure during firing cycle ........................................................................................................... 2
Smoke escaping from around smoke box cover................................................................................. 11
Water heater fails to start..................................................................................................................... 1
Water temperature gage indicates water overheating......................................................................... 12
4-8
