Install Instructions

68
12 Troubleshooting
Table 12E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface
Installation & Service Manual
ERROR CODE DESCRIPTION CORRECTIVE ACTION
E21
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
One or both of the outlet sensors has
opened or shorted.
• Check the sensor and its associated wiring. Repair
or replace the sensor or wiring if damaged.
• Measure the resistances of the sensors and
compare the resistances to the tables on page 62.
Replace if necessary.
E22
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
The inlet sensor is open.
• Check the sensor and its associated wiring. Repair
or replace the sensor or wiring if damaged.
E23
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
display to reset.)
The inlet sensor is shorted.
b01
The temperature has reached the set point
+ 4°F.
• None
b02
The main control board has received a call
for heat too quickly after the previous call for
heat has ended.
• The control board will release the call for heat after
60 seconds.
• The control board will release the call for heat if the
outlet temperature drops 10°F.
b04
The temperature rise across the heat
exchanger has exceeded 30°F.
• Verify that the system is full of water and that all air
has been properly purged from the system.
• Check for 120 vac to the pump motor on a call
for heat. If voltage is not present, check the wiring
on the pump relay back to the main control board.
Replace the main control board if necessary.
• If 120 vac is present on a call for heat and the
pump is not operating, replace the pump.
• Scale accumulation in the heat exchanger. Verify
that the water chemistry meets the requirements
listed in Section 5 - System Piping.
n03
The fan speed is being limited due to the
temperature rise across the heat exchanger
exceeding 25°F.