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Figure 4:
ERROR CODES
ERROR CODES:
Figure 4 lists the error codes that may be displayed on the heater display board.
Contact a qualifi ed service company for assistance.
Code
Description
Information
bD
Internal fault/power-up
error
On initial trial for ignition. Automatic reset is immediate once the gas valve relay
check results are acceptable.
bD
Gas valve sensed
as “ON” error
If valve is open when it should be closed the heater will shut down and go into
lockout. Blower will operate until error condition is corrected. Automatic restart
2 minutes after error is corrected.
bD
Gas valve sensed
as “OFF” error
If valve is closed but fl ame is sensed the blower will run for 5 s then start a new
ignition sequence. If error occurs 10 times during a call for heat the control will
go into lockout. Automatic reset is 60 minutes.
bD
Data retrieval error
If control input data is corrupted the heater will shut down and go into lockout.
HF
Flame present with gas
valve “OFF” error
If fl ame is sensed with the gas valve off the control will go into lockout. The
blower will run until error condition is corrected. When corrected, control will
run blower for 5 s then automatically restart after 2 minutes.
PF
Electrical supply wiring
error
This code will display if 120V polarity is reversed, low voltage is detected, or if
the ground path is not suffi cient. Reset is immediate after error is corrected.
AO
Blower vacuum switch
open error
If the blower prover switch does not close after the blower starts the control will
stop the ignition trial go into lockout. The blower will continue to run. Automatic
reset is immediate after the switch closes.
AO
Blower vacuum switch
open when expected
closed error
If the blower prover switch opens unexpectedly during operation the control will
shut down and attempt to re-light. If the switch does not close after the blower
starts the control will go into lockout with the blower running. Automatic reset is
immediate after error is corrected.
AO
Blower vacuum switch
open during post-purge
error
If the blower prover switch opens during the postpurge cycle (heater is not fi r-
ing) the control will display the error code. The post-purge cycle will be com-
pleted once the blower prover switch closes.
AC
Blower vacuum switch
closed when expected
open error
If the blower prover switch is closed before blower start-up the control will not
start the blower. Automatic reset is immediate when the switch opens.