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Issue 2220
Table 17. Conversion Kit Fan Pressure Switch Requirements at Varying Altitudes
Model
Natural to LP/
Propane
High Altitude
Natural Burner
Orifice Kit
High Altitude
LP/Propane Burner
Orifice Kit
High Altitude Pressure switch
0 - 7500 ft
(0 - 2286m)
7501 - 10000 ft
(2286 - 3048m)
7501 - 10000 ft
(2286 - 3048m)
4501 - 7500 ft
(1371 - 2286m)
7501 - 10000 ft
(2286 - 3048m)
030
17H64
14C92
17H65
14A47
14A50
045
11K48
*51W01
11K47
14A47
14A50
070
14A54
14A53
090
14A57
14A54
110
14A46
14A51
*Conversion requires installation of a gas valve manifold spring which is provided with the gas conversion kit.
Pressure switch is factory set. No adjustment necessary. All models use the factory-installed pressure switch from 0-4500 feet (0-
1370 m).
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
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
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.
Figure 69.
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 pre-purge, the hot surface ignitor
energizes.
4. After a 20 second ignitor warm-up period, the gas
valve solenoid opens.
5. Gas is ignited, flame sensor proves the flame, and the
combustion process continues.