Installation Guide
53
TROUBLESHOOTING
FURNACE COMPONENTS
The descriptions below are various functional components that affect the operation and shutting down of this furnace.
Some of these components and their locations are shown in Figure 43 (page 54) or Figure 44 (page 55). If
any component of the furnace must be replaced, use only factory authorized replacement parts specified in the
Replacement Parts List provided online.
#ONDENSATE$RAIN3WITCH The Condensate Drain Switch will shut down the furnace if the condensate drain from
the Collector Pan becomes clogged.
"LOWER,IMIT3WITCH Prevents operation when blower is not operational.
&LAME3ENSORVerifies when a flame has carried over from the igniter to the opposite end burner. If no flame is
detected, the furnace will shut down within 4 seconds.
&LAME2OLL/UT3WITCH Verifies that the burner flames are drawn into the heat exchanger tubes. If the burner
flames are not properly drawn into the heat exchanger, the flame roll-out switch will close the gas valve and initiate
the shutdown cycle.
'AS6ALVEControls the flow of gas to the burners. When the gas valve is energized it automatically opens and
regulates the gas pressure in the manifold.
)NDUCER!SSEMBLYVents products of combustion to the outside.
0RESSURE3WITCHESVerifies that the inducer is drawing the combustion gases through the heat exchanger. The
pressure switch prevents furnace operation with excessive flue/condensate blockage or improper inducer operation.
3UPPLY!IR,IMIT3WITCH Prevents the air temperature leaving the furnace from exceeding the maximum allowable
outlet air temperature.
)FTHEFURNACEFAILSTOOPERATECHECKTHEFOLLOWING
s )STHETHERMOSTATOPERATINGPROPERLY
s !RETHEBLOWERCOMPARTMENTDOORSINPLACE
s )STHEFURNACEDISCONNECTCLOSED
s (ASTHECIRCUITBREAKERTRIPPEDORTHECONTROLBOARDFUSE
BURNEDOPEN
s )STHEGASTURNEDON
s !REANYMANUALRESETSWITCHESOPEN
s )STHElLTERDIRTYORPLUGGED
s )STHEmAMESENSORCOATED2EMOVEANDCLEANWITH
steel wool. $ONOTUSEEMERYCLOTHORSANDPAPER
s )STHEREBLOCKAGEINTHECONDENSATEDRAINSWITCH!LSO
verify that there is no double trapping of condensate.
s )S THE SECONDARY HEAT EXCHANGER FREE OF DEBRIS AND
CLOGS
s )SEVAPORATORCOILCLEANANDFREEOFDEBRIS)FAPPLICABLE
s !REALLTHE,%$SONTHEFURNACECONTROLBOARDCONSTANTLY
/. )F NOT REFER TO Table 17 or the wiring diagram,
Figure 33 (page 39) to determine fault condition.
I
-0/24!.4./4%4HEFURNACEWILLLOCKOUTAFTER
FAILEDATTEMPTSFORIGNITIONANDWILLTRYAGAINEVERY
HOURIFTHECALLFORHEATREMAINS
s )FTHE)NDUCER"LOWERISOPERATINGANDITEMSABOVEHAVE
been verified, check the Blower Limit Switch and reset
if necessary. See Figure 43 (page 54) or Figure 44
(page 55) for component location.
s )FTHEFURNACEOPERATESWHENTHE"LOWER,IMIT3WITCHIS
reset, contact a qualified service technician to identify
and repair the problem.
s )FTHEFURNACESTILLDOESNT OPERATE CHECK THE &LAME
Roll-out Switches and reset if necessary.
s )FTHEFURNACEOPERATESWHENTHE&LAME2OLLOUT3WITCH
is reset, contact a qualified service technician to identify
and repair the problem.
$IAGNOSTIC$ESCRIPTION Green LED Red LED
Control Fault (No Power) Off Off
L1/Neutral Polarity Fault Flash Flash
1 Hour Lockout Alternating Flash
Normal Operation On On
Pressure Switch Closed Fault On Flash
Pressure Switch Open Fault Flash On
Open Limit Switch Fault Flash Off
$IAGNOSTIC$ESCRIPTION Yellow LED
Low Flame Sensor Signal Continuous Flash
Flame Present On
4ABLEControl Board Fault Conditions