Table 2-2. Unit Troubleshooting (Continued)
TEST OR INSPECTION
WATER HEATER FLAME FAILS DURING FIRING CYCLE. (Cont)
Check for loose fuel pump drive coupling.
If a drive coupling is loose, tighten fuel pump drive coupling.
Refer to paragraph 2-39.
If drive coupling is tight, proceed to next step.
Check for defective fuel pump. Fuel pump pressure should be 75 to 80 psi
(517 to 552 kPa).
If fuel pressure is not between 75 to 80 psi (517 to 552 kPa), replace or adjust
fuel pump. Refer to paragraph 2-39.
If fuel pressure is correct and problem presents, notify your supervisor.
Check for soot buildup in UV scanner tube or on UV scanner eye. Check for any
blockage in UV scanner tube.
WATER HEATER FUEL PRESSURE GAGE INDICATES PRESSURE IS TOO LOW.
Check for improper fuel pump pressure.
If pressure is out of range, adjust fuel pump pressure to 75 to 80 psi (517 to
552 kPa). Refer to paragraph 2-39.
If fuel pressure is correct proceed to next step.
Check for defective fuel shutoff valve. Close valve and check for leaks. Open valve
and check for leaks.
If valve leaks, replace fuel shutoff valve.
If valve does not leak, proceed to next step.
Check for clogged fuel filter.
If fuel filter is clogged, clean fuel filter. Refer to paragraph 2-41.
If fuel filter is not clogged, proceed to next step.
Check for breaks in fuel hoses and for loose couplings.
If couplings are loose or hoses defective, tighten couplings or replace
If couplings and hoses are serviceable and problem persists, notify your