5
 
11
12 13
 
8.
 
Replace
 
 the outer door and tighten the thumbscrew. (See 
Fig. 11.)
9. Turn 
 
ON
 
 the electrical supply to the furnace. (See 
Fig. 12.)
10. Open the external manual gas valve. (See Fig. 13.)
11. Set the room thermostat to a temperature slightly 
above the room temperature. This will automatically 
signal the furnace to start. The inducer motor will start, 
and the hot surface ignitor will energize. When hot, the 
ignitor will have an orange glow.
12. After about 32 seconds, the gas valve permits gas to flow 
to the main burners where it is ignited. Hot flames begin 
to warm the furnace’s heat exchanger. After a time 
delay of approximately 25-45 sec the furnace blower is 
switched on.
 
NOTE:
 
 If the main burners fail to ignite, the furnace control 
system will go through 3 more ignition cycles. Then, if burn-
ers fail to ignite, the system will lockout. If lockout occurs, 
or the blower does not come on—shut down your furnace and 
call your dealer for service.
13. Set your thermostat to the temperature that satisfies 
your comfort requirements. SUGGESTION: Setting 
the thermostat back a few degrees—and compensating 
for the difference with warmer clothing—can make a big 
difference in your fuel consumption on extremely cold 
days. The few degrees at the top of your thermostat “com-
fort level’’ are the most costly degrees to obtain.
When the room temperature drops below the temperature 
selected on the thermostat, the furnace will switch on auto-
matically. When the room temperature reaches the setting 
selected on the thermostat, the furnace will be automatically 
switched off.
 
Continuous Fan Operation
 
-Some thermostats have a “FAN’’ 
switch with 2 selections: AUTO and ON. When thermostat is 
set on AUTO, the furnace blower cycles on and off, controlled 
by the thermostat. In ON position, the furnace blower runs con-
tinuously except for a 42-62 sec delay at the “call for heat.’’ 
Continuous fan keeps the temperature level in your home more 
evenly balanced. It also continuously filters the indoor air.
 
Comfort Fan™
 
-On all but the 58STA or 58STX, the blow-
er speed can be increased or decreased if desired due to 
change of seasons, large gatherings in your home, etc. Sim-
ple change your “FAN” switch from “on” to “off” (or “auto” 
depending on your thermostat), and then return to “on.”
The blower will switch to the next highest speed. There 
are at least 3 speeds to choose from. If the blower is run-
ning on its highest speed, a request to change will direct 
the blower to return to its lowest speed.
 
SHUTTING DOWN YOUR FURNACE
 
Should you ever suspect a malfunction in your furnace, you 
will need to turn the furnace off. The following procedures 
must be followed:
1. Set your room thermostat to the lowest temperature 
setting. (See Fig. 14.)
2.
 
Close
 
 the external manual gas valve (See Fig. 6 on page 4.)
3. Turn 
 
OFF
 
 electrical power to your furnace. (See Fig. 15.)
 
14
15
 
4.
 
Remove
 
 the outer door on your furnace. (See Fig. 8.)
5. Turn the switch on the gas valve to the 
 
OFF
 
 position. (See 
Fig. 16.)
6.
 
Replace
 
 the outer door. (See Fig 11.)
7. If the furnace is being shut down because of a malfunc-
tion, 
 
call
 
 your dealer as soon as possible.
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