507270-03Page 46 of 60 Issue 1917
Priming Condensate Trap
The  condensate  trap  should  be  primed  with  water  prior 
to start-up to ensure proper  condensate  drainage.  Either 
pour  10  .  oz.  (300  ml)  of  water  into  the  trap,  or  follow 
these steps to prime the trap:
1.  Follow  the  lighting  instructions  to  place  the  unit  into 
operation.
2.  Set the thermostat to initiate a heating demand.
3.  Allow the burners to re for approximately 3 minutes.
4.  Adjust  the  thermostat  to  deactivate  the  heating 
demand. 
5.  Wait  for  the  combustion  air  inducer  to  stop.  Set  the 
thermostat  to  initiate  a  heating  demand  and  again 
allow the burners to re for approximately 3 minutes.
6.  Adjust the thermostat to deactivate the heating demand 
and wait for the combustion air inducer to stop. At this 
point, the trap should be primed with sufcient water to 
ensure proper condensate drain operation.
If  you  do  not  follow  these  instructions  exactly,  a  re 
or  explosion  may  result  causing  property  damage, 
personal injury or death.
 WARNING
Gas Valve Operation
See Figure 69
1.  STOP! Read the  safety  information  at  the beginning 
of this section.
2.  Set the thermostat to the lowest setting. 
3.  Turn OFF all electrical power to the unit.
4.  This furnace is equipped with an ignition device which 
automatically lights the burners. Do not try to light the 
burners by hand.
5.  Remove the upper access panel.
6.  Move gas valve switch to OFF. See Figure 69.
7.  Wait  ve  minutes  to  clear  out  any  gas.  If  you  then 
smell gas, STOP! Immediately call your gas supplier 
from  a  neighbor’s  phone.  Follow  the  gas  supplier’s 
instructions. If you do not smell gas go to next step.
Figure 69. 
8.  Move gas valve switch to ON. See Figure 69.
9.  Replace the upper access panel.
10.  Turn on all electrical power to the unit.
11.  Set the thermostat to desired setting.
NOTE: When  unit  is  initially  started,  steps  1  through 
11 may need to be repeated to purge air from gas line.
12.  If the appliance will not operate, follow the instructions 
“Turning  Off  Gas  to  Unit”  and  call  your  service 
technician or gas supplier.
Turning Off Gas to Unit
1.  Set the thermostat to the lowest setting.
2.  Turn off all electrical power to the unit if service is to 
be performed.
3.  Remove the upper access panel.
4.  Move gas valve switch to OFF. 
5.  Replace the upper access panel.
Failure To Operate
If the unit fails to operate, check the following:
1.  Is the thermostat calling for heat?
2.  Are access panels securely in place?
3.  Is the main disconnect switch closed?
4.  Is there a blown fuse or tripped breaker?
5.  Is the lter dirty or plugged? Dirty or plugged lters will 
cause the limit control to shut the unit off.
6.  Is gas turned on at the meter?
7.  Is the manual main shut–off valve open?
8.  Is the internal manual shut–off valve open?
9.  Is the unit ignition system in lockout? If the unit locks 
out again, inspect the unit for blockages.
Heating Sequence of Operation
1.  When thermostat calls for heat, combustion air inducer 
starts.
2.  Combustion  air  pressure  switch  proves  blower 
operation.  Switch  is  factory  set  and  requires  no 
adjustment.
3.  After  a  15  second  pre-purge,  the  hot  surface  ignitor 
energizes.
4.  After  a  20  second  ignitor  warm-up  period,  the  gas 
valve  solenoid  opens.  A  4-second  “Trial  for  Ignition” 
period begins.
5.  Gas is ignited, ame sensor proves the ame, and the 
combustion process continues.
6.  If  ame  is  not  detected  after  rst  ignition  trial,  the 
ignition  control  will  repeat  steps  3  and  4  four  more 
times  before  locking  out  the  gas  valve.  The  ignition 
control will then automatically repeat steps 1 through 
6 after 60 minutes. To interrupt the 60 minute period, 
move  thermostat  from  “Heat”  to  “OFF”  then  back  to 
“Heat”. Heating sequence then restarts at step 1.