SERVICING
38
Pressure Regulator
Adjustment
(Under Cap Screw)
Gas Valve
On/Off
Selector
Switch
INLET
OUTLET
Inlet Pressure
Tap
Outlet Pressure
Tap
White-Rodgers Model 36J22 (Single-Stage)
WARNING
HIGH VOLTAGE
Disconnect ALL electrical power and shut off gas supply
before servicing or installing.
Gas
Rate
Range
Nominal
Propane Gas
High Stage 9.7 to 10.3" w.c. 10.0" w.c.
Manifold Gas Pressure
CHECKING HOT SURFACE IGNITOR
120V Mini Ignitor Single Stage -
Furnaces use a 120V car-
bide mini igniter for ignition (part# 20165703) or a Silicon
Nitride igniter (part# 0130F00008). The normal operating
temperature is approximately 2550°F - 2876°F.
WARNING
Disconnect ALL power before servicing.
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.
120V Silicon Nitride Ignitor
- Furnaces with a 120V
silicone nitride igniter. The normal operating tempera-
ture is approximately 2156°F - 2678°F. At room tem
-
perature the igniter ohm reading should be from 37
- 68 ohms.
WARNING
Line Voltage now present.
6. After checking and/or replacing of hot surface ignitor,
reinstall burner compartment door and verify proper
unit operation.
CHECKING FOR FLASHBACK
Flashback will also cause burning in the burner venturi, but
is caused by the burning speed being greater than the gas-
air flow velocity coming from a burner port.
Flashback may occur at the moment of ignition, after a burn-
er heats up or when the burner turns off. The latter is known
as extinction pop.
Since the end results of flashback and delayed ignition can
be the same (burning in the burner venturi) a definite at
-
tempt should be made to determine which has occurred.
If flashback should occur, check for the following:
1. Improper gas pressure - Adjust to proper pressure
(See
CHECKING GAS PRESSURE
).
2. Check burner for proper alignment and/or replace
burner.
3.
Improper orifice size - Check orifice for obstruction.
CHECKING PRESSURE SWITCH
The pressure switch a safety device to prevent the combus-
tion cycle from occurring with inadequate venting caused by a
restricted or blocked vent pipe on the 80% and 90% furnaces.
WARNING
HIGH VOLTAGE
Disconnect ALL power before servicing or in
-
stalling this unit. Multiple power sources may
be present. Failure to do so may cause proper
-
ty damage, personal injury or death.
1. Remove burner compartment door to gain access to
pressure switch(es).
2. Remove wires from the pressure switch(es) electrical
terminals.
3. Using a VOM check from common terminal to NC
(Normally Closed) - should read open.
If switch reads as above proceed to Step 4, otherwise re-
place control.
4. Remove the pressure control hose from the control
and interconnect with a manometer as shown in the
following figures.
