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Servicing should only be performed by a Quali
fi
ed Service Technician
TROUBLESHOOTING
Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous
operation. Always disconnect power to the water heater before servicing. Failure to comply could result in
severe personal injury, death, or substantial property damage.
Never jumper (bypass) any device except for momentary testing as outlined in the Troubleshooting chart.
Severe personal injury, death, or substantial property damage can result.
Before troubleshooting:
1. Have the following items:
a. Voltmeter that can check 120 VAC, 24 VAC, and 12 VDC.
b. Continuity checker.
c. Contact thermometer.
2. Check for 120 VAC (minimum 102 VAC to maximum 132 VAC) to water heater.
3. Make sure all external limit controls are installed and operating.
Check the following:
1. Wire connectors to control module are securely plugged in at the module and originating control.
2. Gas pressures:
• Maximum: 14 inches w.c. (Natural and LP) with no
fl
ow (lockup) or with water heater on
• Minimum: 4 inches w.c. (natural), 8 inches w.c. (LP) with gas
fl
owing (verify during water heater
startup)
Check control module fuses
Note:
ALWAYS check control module fuses before replacing control module or any major components
(blower, etc.). If one of these fuses is blown, it can prevent the control module or other components
from operating.
1. Turn OFF power to the water heater at the external line switch.
2. Remove top access cover.
3. Remove the control module cover.
4. Inspect fuses F1, F2 and F3, see Figure below.
Figure 8. Control Module Fuses
F3 - .80 AMP FUSE
24V DC POWER SUPPLY
F1 - 5 AMP FUSE
PUMPS
F2 - 3.15 AMP FUSE
BLOWER
