Service Manual

49
Troubleshooting
System Observations
Water Heater Fault: Water heater does NOT operate.
Display Error Code: Water heater display does NOT
operate – blank display.
WARNING
120 volt potential exposure. Use caution making
voltage checks to avoid personal injury.
CAUTION
Use caution to NOT damage connectors when
making voltage measurements or jumping terminals.
Check main power supply to water heater
– fuse, circuit breaker, plug receptacle,
line cord, or wiring to water heater.
Check to make sure switch on front of
control panel is in the ON position.
Verify primary voltage at the transformer.
Verify secondary voltage at the control board.
Refer to control board illustration. Voltage at
primary pins P2(1) & P2(3) will be 110-120. If not,
check line in pin P3(1) & P3(4). Check line cord
with volt meter. Replace line cord if defective.
Refer to control board illustration. Voltage at
secondary pins P4(1) & P4(2) will be 24 VAC. If
not, replace transformer or wire harness.
Does the water heater display operate? Does
the combustion blower start to operate?
Increase thermostat setting if the tank is warm.
Display operates – see next page.
Is 24 VAC present
between the red
and black wire pin
connections on
the back of the
control display?
Check wires for
proper termination to
control display. Are
wire terminations
connected properly to
the control display?
Is 24 VAC present between the E-COM screw
terminals P9(2) & P9(3) on the control board.
Replace the
control board.
Check the wire harness
for proper continuity.
Replace the
control board.
Make proper wire
terminations.
N
N
N
N
N
N
Y
Y
Y
Y
Y
Y
Y
Y
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