Allied 92G1UH-P, Installation Instructions Manual

507270-03

Page 45  of  60

Issue 1621

Priming Condensate Trap

The condensate trap should be primed with water prior to 

start-up to ensure proper condensate drainage.  Either pour 

10 fl. 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 fire 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 fire 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 sufficient water 

to ensure proper condensate drain operation.

If  you  do  not  follow  these  instructions  exactly,  a  fire 

or explosion may result causing property damage, 

personal injury or death.

  WARNING

Gas Valve Operation (Figure 65)

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 65.

7.  Wait  five  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.

8.  Move gas valve switch to 

ON.  

See Figure 65.

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 filter dirty or plugged?  Dirty or plugged filters 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 prepurge, 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, flame sensor proves the flame, and the 

combustion process continues.

6. 

If flame is not detected after first 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.

Figure 65