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CHECK WATER HEATER T & P RELIEF VALVE
1. Inspect the T & P Relief Valve and lift the lever to verify flow.
Before operating any T & P Relief Valve, ensure that it is
piped with its discharge in a safe area to avoid severe scald
potential. Read System Piping section on Page 36 before
proceeding further.
Safety T & P Relief Valves should be re-inspected AT LEAST
ONCE EVERY THREE YEARS, by a licensed plumbing
contractor or authorized inspection agency, to ensure that the
product has not been affected by corrosive water conditions and
to ensure that the valve and discharge line have not been altered
or tampered with illegally. Certain naturally occurring conditions
may corrode the valve or its components over time, rendering the
valve inoperative. Such conditions are not detectable unless the
valve and its components are physically removed and inspected.
This inspection must only be conducted by a qualified service
technician. Failure to re-inspect the water heater T & P Relief
Valve as directed could result in unsafe pressure buildup, which
can result in severe personal injury, death, or substantial property
damage.
Following installation, the valve lever must be operated AT
LEAST ONCE A YEAR to ensure that waterways are clear.
Certain naturally occurring mineral deposits may adhere to the
valve, rendering it inoperative. When manually operating the
lever, water will discharge and precautions must be taken to
avoid contact with hot water and to avoid water damage. Before
operating lever, check to see that a discharge line is connected
to this valve directing the flow of hot water from the valve to a
proper place of disposal. Otherwise severe personal injury may
result. If no water flows, valve is inoperative. Shut down the water
heater until a new T & P Relief Valve has been installed.
2. After following the above warning directions, if the T & P
Relief Valve weeps or will not seat properly, replace the T
& P Relief Valve. Ensure that the reason for T & P Relief
Valve weeping is the valve and not over-pressurization
of the system due to the lack of a thermal expansion tank
waterlogging or undersizing.
INSPECT IGNITION AND FLAME SENSE ELECTRODES
1. Remove the ignition and flame sense electrodes from the
water heater heat exchanger access cover.
2. Remove any deposits accumulated on the ignition/flame
sense electrode. If the electrodes cannot be cleaned
satisfactorily, replace with new ones.
3. Replace ignition/flame sense electrode, making sure gasket
is in good condition and correctly positioned.
CHECK IGNITION GROUND WIRING
1. Inspect water heater ground wire from the heat exchanger
access cover to ground terminal strip.
2. Verify all wiring is in good condition and securely attached.
3. Check ground continuity of wiring using continuity meter.
4. Replace ground wires if ground continuity is not satisfactory.
CHECK ALL WATER HEATER WIRING
1. Inspect all water heater wiring, making sure wires are in
good condition and securely attached.
CHECK CONTROL SETTINGS
1. Use the UIM control display to access MENU and check
all parameter settings. Adjust settings if necessary. Refer
to the XP Water Heater Service Handbook for adjustment
procedures.
2. Check settings of external limit controls (if any) and adjust
if necessary.
PERFORM START-UP AND CHECKS
1. Start water heater and perform checks and tests specified in
Start Up section of this manual.
CHECK BURNER FLAME
1. Inspect flame through observation window.
2. If the flame is unsatisfactory at either high fire or low fire,
turn off water heater and allow water heater to cool down.
Remove the burner (see Figure 77 below) and clean it
thoroughly using a vacuum cleaner or compressed air. Do
not use compressed air to clean burner if performed inside
a building.
3. When replacing the burner, ensure gasket is in good
condition and positioned correctly (Figure 77).
CHECK FLAME SIGNAL
1. At high fire the flame signal shown on the display should be
at least 10 microamps.
2. A lower flame signal may indicate a fouled or damaged flame
sense electrode. If cleaning the flame sense electrode does
not improve, ground wiring is in good condition, and ground
continuity is satisfactory, replace the flame sense electrode.
3. See Troubleshooting section in the XP Water Heater Service
Handbook for other procedures to deal with low flame signal..
Figure 77. Burner Assembly
