Comfort-Aire GDD95A Downflow Furnaces - Manual (Page 9)

9
STARTUP & SHUTDOWN
Figure 1. Gas Valves
SINGLE STAGE VALVE
TWO - STAGE VALVE
STARTING THE FURNACE
1. Make sure the filter is clean and in place.
2. Make sure the vent system is properly installed.
3. Set the thermostat to the lowest setting.
4. Close the manual gas valve outside the furnace.
5. Turn off all electric to the furnace.
6. Remove the door from the burner compartment.
7. Set the gas valve switch or knob to the OFF position.
See Figure 1 for gas valve switch or knob location.
8. Wait 5 minutes. If there is any smell of gas, see “WHAT
TO DO IF YOU SMELL GAS” on page 4.
9. Set the gas valve switch or knob to the ON position.
10. Turn on all electric to the furnace.
11. Open the manual gas valve.
12. Turn the thermostat back up to force ignition.
13. Observe operation, including burners. If burners fail
to ignite, call a licensed HVAC technician.
14. Replace the door on the burner compartment.
SHUTTING DOWN THE FURNACE
IMPORTANT! IF YOU NEED TO SHUT DOWN YOUR
FURNACE FOR SERVICE OR MAINTENANCE, SHUT
OFF THE GAS VALVE TO THE FURNACE BEFORE
TURNING OFF THE ELECTRICAL SERVICE.
NOTE: Your furnace may be equipped with one of three
types of gas valves. Remove the door panel from the front
of the furnace and determine which valve type matches
your installation in Figure 1. Move the switch to the OFF
Position.
If your installation has a manual gas shutoff valve on the
gas supply pipe, shut this off, then shut off the electric
to the furnace.
1. Set the thermostat to the lowest setting.
2. Close the manual gas valve outside the furnace.
3. Turn electric to the furnace off.
4. Open the door to the burner compartment.
5. Set the gas valve switch or knob to the OFF position.
6. Replace the door on the burner Compartment.
TROUBLESHOOTING
If the furnace fails to operate check the following:
1. Is the thermostat setting correct?
2. Are the blower compartment door(s) in place?
3. Has the circuit breaker tripped or the control board
fuse burned open?
4. Is the gas turned on at the manual shutoff?
5. Is the filter dirty or clogged?
If the furnace still doesn’t operate, contact a licensed
HVAC technician