5
12
13
14
15
16
17
9. Open the external manual gas valve. (See Fig. 17.)
10. 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.
11. After 15 to 70 sec, 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 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. If burners
still fail to ignite, the system will lockout. (Under some cir-
cumstances the furnace may reset from lockout and attempt
to ignite if a call for heat still exists.) If lockout occurs or the
blower does not come on, refer to the shutdown procedures
on the furnace or see “Shutting Down Your Furnace” section
in this manual, and call your dealer for service.
12. 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. The few degrees
at the top of your thermostat “comfort 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 automatically
switch off.
Some thermostats have a “FAN’’ switch with 2 selections,
AUTO and ON. When thermostat is set on AUTO, the fur-
nace blower cycles on and off, controlled by the thermostat.
In ON position, the furnace blower runs continuously
except for a 77-sec delay at the “call for heat.’’ This keeps
the temperature level in your home more evenly balanced.
It also continuously filters the indoor air. When the FAN
switch is moved from ON to AUTO, the furnace blower will
continue running for 90 sec before stopping.
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. 18.)
2. Close the external manual gas valve. (See Fig. 8.)
3. Turn off electrical power to your furnace. (See Fig. 19.)
18
19
4. Remove the control access door on your furnace. (See
Fig. 10 or 11.) On upflow furnaces, removing the blow-
er access door is not required.
5. Turn the control knob on the gas valve to the OFF posi-
tion. (See Fig. 20.)
6. Replace the control access door. (See Fig. 14 or 15.)
7. If the furnace is being shut down because of a malfunc-
tion, call your dealer as soon as possible.
Performing routine maintenance
With proper maintenance and care, your furnace will oper-
ate economically and dependably. Basic maintenance,
which can easily be accomplished by someone who fol-
lows the directions, is found on this and the following
pages. However, before beginning maintenance, follow
these safety precautions:
WARNING
Turn off electrical power supply to your furnace
before removing the access doors to service or
perform maintenance. A failure to follow this
warning could result in personal injury or death.
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