Single Stage Multi Position Furnace
Service Manual
47
440 08 2001 02
HONEYWELL SV9541 “SMART VALVE” Trouble shooting
The 6 + X designation indicates a combination of flash codes: 6
flashes shows the control is in soft lockout, followed by X flashes to
indicate the reason the control went into soft lockout. Last status
code indicates repair to address first
LED
STATUS
INDICATES
CHECK/REPAIR
Off
No power to system control.
Line voltage input at L1 and Neutral connectors on ST9160B
Fan Timer.
Low voltage (24V) power at 24 VAC and COM terminals on
ST9160B
System wiring harness is in good condition and securely
connected.
Heartbeat
Bright
–
Dim
Normal indication whenever the system is powered,
unless some abnormal event has occurred.
Not Applicable
--
Normal Operation (stand by or call for heat)
2 Flashes
Pressure switches closed when it should be open
(i.e. when call for heat begins).
(Combustion blower is not energized until pressure
switches opens)
Pressure switches stuck closed (system will wait for pres-
sure switch to open).
Pressure switches miswired or jumpered.
3 Flashes
Pressure switches , open when they should be closed
(i.e. longer than 30 seconds after combustion blower/
inducer is energized).
System goes into 5--minute delay period, with com-
bustion blower/inducer off. At end of the 5--minute
delay, another cycle will begin.
Ignition system control switch must be in the ON position.
Pressure switches operation, tubing, and wiring.
Restrictions in furnace air intake or vent piping.
4 Flashes
Main Limit or Roll Out Switch is open.
Combustion blower is energized, Circulating blower is
energized heat speed.
Main limit switch.
Manual reset burner rollout switch.
Limit and rollout switch wiring is in good condition and se-
curely connected.
Duct restriction/overfire.
5 Flashes
Flame signal sensed out of proper sequence.
Combustion blower is energized, Circulating blower is
energized heat speed after the “ON” delay.
Flame at pilot burner.
6 Flashes
+
1 Flash
Soft Lockout.
Failed to light pilot during 90 sec. trial for ignition
Combustion air blower is de--energized, Circulating
blower is de--energized after the “OFF” delay.
After 5--minute delay time, control system will reset
and initiate a new ignition sequence,
Gas supply off or pressure too low or high for appliance to
operate.
Damaged or broken HIS element
Flame sense rod contaminated or in incorrect position.
Pilot burner located in incorrect position.
Pilot burner lead wires are in good condition and popery con-
nected.
Pressure switches operation, tubing, and wiring.
6 Flashes
+
2 Flashes
Soft Lockout.
Last failure was Flame Sense lost during run.
Maximum recycle count exceeded
Combustion air blower is de--energized, Circulating
blower is de--energized after the “OFF” delay.
After 5--minute delay time, control system will reset
and initiate a new ignition sequence,
Gas supply off or pressure too low or high for appliance to
operate.
Flame sense rod contaminated or in incorrect position.
Pilot burner located in incorrect position.
Pilot burner lead wires are in good condition and properly
connected.
Cycling, pressure switch
Condensate drain blocked
Pressure switches operation, tubing, and wiring.