Service manual

77
Installation & Service Manual
13 Troubleshooting (continued)
Table 13-4 (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
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 71. 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
+ 10°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 60°F.
• Verify that the system is full of water and that all air
has been properly purged from the system.
• Verify that the boiler is piped properly into the heating
system. Refer to Section 6 - Hydronic Piping
for the proper piping methods for the Cadet
boiler.
• Check for 120 vac to the boiler pump motor on a call
for heat. If voltage is not present, check the wiring
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 boiler
pump is not operating, replace the pump.
• Verify that the boiler pump is set to the proper speed
or that the pump is the proper size. Reference
Section 6 - Hydronic Piping for boiler
pump specifications.
n03
The fan speed is being limited due to the
temperature rise across the heat exchanger
exceeding 55°F.