System Observation

For models with Direct Spark Ignition

Does combustion blower operate?
Error code #29 on display. Refer to Control Board
illustration. Measure voltage between terminals P7(3) &
P7(5) on the “inducer” output (make sure the control display
shows “heating” in the status mode, if not increase the
setpoint). Is there 110-120 VAC?
Replace control board if display
shows “heating” and no voltage is
present to the blower harness.
Make sure there are no error
codes for the temperature
sensors (following sections)
before replacing control board.
Check the voltage at the connection to the
blower. Is 110-120 VAC present?
Can sparking be seen/heard at the
spark rod to the burner?
Does Main Burner Light?
Error code #62 on display. See
main burner lights, no flame signal
in section “Combustion System
Testing and Replacement”
Does burner continue until
thermostat set point is reached?
See setting display in Service Mode
and displaying temperature
sensors.
Error code #63 on display. (see
“Combustion System Testing and
Replacement”)
Does blower post-purge for 30
seconds?
System okay
N
Y
N
N
N
Y
Y
Y
Y
From previous page
N
CAUTION

Use caution not to damage connectors when

making voltage measurements or jumping terminals

WARNING
120 volt potential exposure. Use cautionmaking voltage checks to avoid personal injury.
123
8
6
5
4
3
1
12
1
4
1
3
3
2
1
1
5
3
P2P4P5 P7P3

CONTROL BOARD

P10P9J1
Y
Replace wire harness.Replace blower. N
Remove high voltage wire connected at the spark rod and
hold approximately ¼" from metal ground with insulated
pliers during the ignition cycle (3 second spark trial period).
Is there spark to ground?
N
Check resistance of high voltage
cable. Resistance should be 0-1
ohms. If resistance is high, replace
spark cable. If spark cable is good,
replace Control Board.
Check continuity of spark rod and spark rod
gap to burner.
(see section “Spark Rod Gap Adjustment”)
Y
Y
19
Check to see if control display shows any other error
codes (29, pressure switch, 26, vent safety switch, or 65,
high limit). If so, refer to the appropriate section for
testing and replacement.
19