Service Manual

21
21
Error
Code
Definition of Code Cause of Problem and Actions Taken to Correct
No
code –
blank
display
No power to the unit
or switch is off.
• Check power supply to the water heater.
• Make sure water heater is plugged in and the breaker is on.
• Check if there is 120 volts power supply to the LINE connections on the control
board.
• Verify 24 volts at display.
• Check for loose wires, defective transformer.
• Check wire harness connections from display to the control board.
9,22
Low flame sense
signal
• Check microamp output of flame sense
• Inspect flame sensor and wire
• Inspect burner for debris
49
Voltage too low or
high
• Measure the incoming line voltage.
• Voltage should be 115-125 volts.
• If the voltage is not within this range or there is drastic fluctuation, then have the
incoming power supply checked.
• If the line voltage is satisfactory, check the output from the transformer to make
sure it is 22-26 volts.
• Replace transformer or wiring if defective.
53
AC Inputs phase
reversed
• Check the module and display connections.
• Check the module power supply and make sure that frequency, voltage and VA
capacity of the transformer meet specifications.
• Check to make sure the wiring connections on the control module from terminals
J4-10 and J8-2 are connected together.
62 Fan speed not proved
• Check the pulse width modulation (PWM) wire harness connection from the
blower to the control module.
• Make sure the pin terminals make solid contact.
• Measure the resistance of each wire in the wire harness from the terminal ends.
• Replace wire harness if defective.
• If value remains out of range, this hold will change to lockout 123 (defined below)
67
Normally closed vent
safety circuit opened
• Check wiring to the normally closed blocked vent switch at draft hood
• Use a voltmeter to find out if the blocked vent switch is open.
• If so, determine the cause (vent restriction, adequate draft)
• If limit switch is closed, check wiring for shorts.
• Measure continuity.
• If limit switch and wiring check O.K., replace control module.
80
High Limit (Overheat
Condition)
• Check the wiring from the water temperature sensor to the control module.
•
Measure the resistance of each outside wire to the center wire. Measure the tank
temperature and compare with the chart below.
• If either outside wir
e has a much different resistance reading, replace the sensor.
• Make sure the sensor is securely held inside the well with the clip.
• If the problem persists and the sensor and wiring check O.K., then replace the
control module.
NOTICE
The ICON control system can produce soft and hard lockouts. Soft lockouts are displayed if active
and are not stored in Diagnostic Mode history. The control will periodically attempt to resume
normal operation when in soft lockout conditions. If the system resumes normal operation a soft
lockout will clear instantly; hard lockouts will display if active and require manual reset. Up to ten
previous Hard lockouts are logged chronologically (newest first) in Diagnostic Mode history.