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5. The water heater is shipped with three (3) spare fuses in a plastic bag attached to the control module
cover.
6. If necessary, replace open fuse (F3 is .80 amps, F2 is 3.15 amps, and F1 is 5 amps).
Note: Fuses F1, F2 and F3 are all slow blow fuses.
Do not jumper fuse or replace with any fuse except as specifi ed. Failure to comply could result in severe
personal injury, death, or substantial property damage.
7. Install control module cover and top access cover after fuse inspection.
8. Restore power to the water heater at the external line switch and verify water heater operation (Start-up
section in the XP Water Heater Instruction Manual) after completing water heater service.
TROUBLESHOOTING CHART - NOT VISIBLE ON DISPLAY
FAULT
No Display
No Burner Operation
Unit Does Not
Modulate Above 50%
28
Table 8. Troubleshooting Chart - Not Visible On Display
CAUSE
- No 120 VAC supplied to unit.
- No voltage through the switch.
- Bad display board.
- Bad main control board.
- Blown fuse.
- Main control board temperature
set point satisfi ed.
- Remote thermostat satisfi ed.
- Unit locked out on fault.
- Water heater controlled by BMS. •
- Flue sensor open.
Servicing should only be performed by a Qualifi ed Service Technician
CORRECTIVE ACTION
•
Check external line switch, or breaker.
•
Check position of ON/OFF switch. Turn
switch to the ON position.
•
Check 120 VAC through the ON/OFF
switch.
•
Check wiring harness connection
between display board and main control
board. Connect harness at both points.
•
Replace switch.
•
Replace board.
•
Replace the main control board.
•
Replace fuse F3 on the main control
board, see Page 27 of this Service
Handbook.
•
Review temperature setting.
•
Check display for Standby status.
•
Review remote thermostat setting.
•
Consult display for specifi c fault. Refer
to fault descriptions on Pages 28 - 37
of this Service Handbook for corrective
actions.
•
Check Current Fault section in Display
Menu.
Check BMS parameter settings.
•
Verify that the fl ue sensor is located in
the fl ue outlet.
•
Check wiring connections at the fl ue
sensor.
•
Check the resistance of the fl ue sensor
and compare to Table 11.2 on Page 38
of this Service Handbook.
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Table of Contents
Troubleshooting
