Service Guide

SERVICING
38

 

S

R R  S  S
S R SR R S S 

 R SRS   RS

R 
 S  S RR  RS JR R 
7. Turn on gas to furnace and check for leaks. If leaks are
found, repair and then reinstall burner compartment door.
8. Turn on electrical power and verify proper unit operation.
Pressure Regulator
Adjustment
(Under Cap Screw)
Gas Valve
On/Off
Selector
Switch
INLET
OUTLET
Inlet Pressure
Tap
Outlet Pressure
Tap

Gas Valve On/Off
Selector Switch
Inlet
Pressure
Ta p
Pressure Regulator
(under cap screw)
Outlet
Pressure
Ta p


 

S
 R R  S  S S
R SR R S
Gas Rate Range Nominal
Propane Gas High Stage 9.7 to 10.3" w.c. 10.0" w.c.
Manifold Gas Pressure

      furnaces use a 120V
carbide mini igniter for ignition. (part# 20165703) or a
Silicon Nitride igniter (part# 0130F00008) The normal
operating temperature is approximately 2550°F - 2876°F.

S

R R SR

1. Remove burner compartment door to gain access to the
ignitor.
2. Ignitor cool - approximately 70 - 77°F.
3. Disconnect the ignitor from the Ignition Control.
4. Using an ohmmeter measure the resistance of the ignitor:
Mini Igniter : Carbide Mini Igniter should read between 30
to 300 ohms.
5. Reconnect ignitor.
    - furnaces with a 120V
silicone nitride igniter; The normal operating temperature
is approximately 2156°F-2678°F. At room temperature
the igniter ohm reading should be from 37-68 ohms.

   RS

6. After checking and/or replacing of hot surface ignitor,
reinstall burner compartment door and verify proper unit
operation.

Flashback will also cause burning in the burner venturi, but is
caused by the burning speed being greater than the gas-air
ow velocity coming from a burner port.
Flashback may occur at the moment of ignition, after a burner
heats up or when the burner turns o󰀨. The latter is known as
extinction pop.
Since the end results of ashback and delayed ignition can
be the same (burning in the burner venturi) a denite attempt
should be made to determine which has occurred.
If ashback should occur, check for the following:
1. Improper gas pressure - adjust to proper pressure (See
S-307 CHECKING GAS PRESSURE)..
2. Check burner for proper alignment and/or replace burner.
3. Improper orice size - check orice for obstruction.