Carrier 58ZAV - Manual (Page 5)

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4. Remove the furnace access door(s).
a. Downflow/Horizontal—remove blower door after re­
moving 2 screws first, then remove the control door.
(See Fig. 10.)
b. Upflow—remove control door. (See Fig. 11.)
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5. Tbrn the control knob on the gas valve to the OFF position
and wait 5 minutes. (See Fig. 12.)
6. After waiting 5 minutes, turn the control knob on the gas
valve to the ON position. (See Fig. 13.)
7. Replace the access door(s). See Fig. 14 for upflow and Fig.
15 for downflow. Replace control door first on downflow
furnaces. Then replace blower door (secure with 2 screws).
8. Tbrn ON the electrical supply to the furnace. (See Fig. 16.)
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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 approx­
imately 45 seconds, 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 burners
fail to ignite, the system will lockout. If lockout occurs, or the
blower doesn’t come on—shut down your furnace and call your
dealer for service.
12. Set your thermostat to the temperature that satisfies your
comfort requirements. SUGGESTION: Setting the ther­
mostat back a few degrees—and compensating for the dif­
ference 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 “comfort level” are
the most costly degrees to obtain.
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When the room temperature drops below the temperature se­
lected on the thermostat, the furnace will be switched on auto­
matically.
When the room temperature reaches the degree
selected on the thermostat, the furnace will be automatically
switched off.
Some thermostats have a “fan” switch with 2 selections: AUTO
or ON. When set on AUTO, the furnace blower cycles on and
off, controlled by the thermostat. In the ON position, the fur­
nace blower runs continuously except for a 45-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.