23
(Direct Ignition Furnaces)
Direct ignition furnaces do not have a pilot. Ignition is
accomplished by a silicon carbide hot surface ignitor. A
control module takes care of all timing functions. After
lighting,thecontrolmoduleusestheignitorasaame
sensor,shuttingoffgasshouldtheamegoout.There
are no external relays or timing devices.
1. Set the thermostat to the lowest setting.
2. Turn off all electric power to the appliance.
3. Remove the furnace door and turn off the gas valve:
• Honeywell: push in and turn the gas control knob
clockwise to OFF. See Figure 30.
• Robertshaw: push the gas control lever
to the OFF position. See Figure 31.
4. Wait ten (10) minutes to clear out any gas. If you smell
gas, and follow the Safety Information on page
22. If you do not smell gas, proceed to next step 5.
5. Set the thermostat MODE the ON position.
6. Turn the gas valve ON:
• Honeywell: push in and turn gas control knob counter-
clockwise to ON (Figure 30).
• Robertshaw: push the gas control lever to the ON position
(Figure 31).
7. Replace the furnace door.
8. Turn on all electric power to the appliance.
9. Change the thermostat mode to and the
temperature selector to a desired temperature level.
The igniter should light in approximately 75 seconds.
If the appliance will not operate, see How to Shut Off
Gas - Direct Ignition and call your service technician or
gas supplier.
In the event of any ashback or explosion,
immediately shut off the furnace and call your service
technician.
How to Shut Off Gas - Direct Ignition
1. Set the thermostat to the lowest setting.
2. Turn off all electric power to the appliance before
servicing unit.
3. Set the furnace On-Off Switch to OFF.
• Honeywell(Figure 30): Turn gas control knob clockwise
to OFF, Robertshaw (Figure 31): Push the gas control
lever to OFF.
• Foroil,shutoffallvalves.
4. Replace the furnace door.
(Oil Gun Furnaces)
If your furnace model number begins with M5S*, the
furnace is equipped with an ignition device which
automatically lights the burner.
.
1. Open all valves in the oil line.
2. Verify the fire door is closed.
3. Set the furnace On-Off switch to ON.
4. Set the thermostat to the desired setting.
M5 oil gun furnaces may be converted to gas gun
in the field by using the proper conversion kit listed in the
Replacement Parts List.
M1B
(Gas Gun Furnaces)
If your furnace model number begins with M1B, the furnace
does not have a pilot. Ignition is accomplished by a silicon
carbide hot surface ignitor. A control module takes care
of all lighting and timing functions. There are no external
relays or timing devices.
1. Before operation, smell for gas all around the furnace,
especially near the oor because some gases are
heavierthanairandwillsettleontheoor.
.
2. Set the thermostat to the lowest setting.
3. Turn off all electric power to the appliance.
4. Turn off the gas valve:
• Honeywell: push in the gas control knob and turn
clockwise to OFF (Figure 30).
• Robertshaw: push the gas control lever to OFF (Figure
31).The lever cannot be placed in the off position unless
it is pushed in slightly.
Figure 30
Figure 30.
Figure 31
Figure 31.
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