58SC0B/58SC1B: Installation, Start–Up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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NOTE: Blower access door must be installed when taking temperature
rise reading. Leaving blower access door off will result in incorrect
temperature measurements.
a. Place thermometers in return and supply ducts as close to furnace
as possible. Be sure thermometers do not see radiant heat from
heat exchangers. Radiant heat affects temperature rise readings.
This practice is particularly important with straight-run ducts.
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine air
temperature rise.
NOTE: If the temperature rise is outside this range, first check:
(1.) Gas input for heating operation.
(2.) Derate for altitude if applicable.
(3.) Return and supply ducts for excessive restrictions causing
static pressures greater than 0.50-in. w.c.
c. Adjust air temperature rise by adjusting blower speed. Increase
blower speed to reduce temperature rise. Decrease blower speed
to increase temperature rise
d. Turn thermostat down below room temperature and remove
blower access door.
e. Refer to the FURNACE CONTROL PROGRAMMING AND
NAVIGATION section of this manual for instructions on
adjusting the blower speed.
f. Repeat steps a through e until termperature rise is within range
on rating plate.
g. When correct input rate and temperature rise is achieved, turn
gas valve ON/OFF switch to OFF.
h. Remove manometer or similar device from gas valve.
i. Reinstall manifold pressure tap plug in gas valve.
6. Adjust heating blower-OFF delay. The blower-OFF delay has four
adjustable settings from 90 sec to 180 sec. Refer to the FURNACE
CONTROL PROGRAMMING AND NAVIGATION section of
this manual for instructions.
Factory off delay setting is 120 sec.
7. Set airflow CFM for cooling. See Table 9-Air Delivery-CFM (with
filter).
8. Adjust cooling blower-OFF dealy. Refer to the FURNACE
CONTROL PROGRAMMING AND NAVIGATION section of
this manual for instructions.
Check Safety Controls
The flame sensor, gas valve, and pressure switch were all checked in the
Start-up procedure section as part of normal operation.
1. Check Main Limit Switch(es)
This control shuts off combustion control system and energizes
air-circulating blower motor, if furnace overheats. By using this
method to check limit control, it can be established that limit is
functioning properly and will operate if there is a restricted duct
system or motor failure. If limit control does not function during
this test, cause must be determined and corrected.
a. Run furnace for at least 5 minutes.
b. Gradually block off return air with a piece of cardboard or sheet
metal until the limit trips.
c. Unblock return air to permit normal circulation.
d. Burners will re-light when furnace cools down.
2. Check draft safeguard switch.
The purpose of this control is to cause the safe shutdown of the
furnace during certain blocked vent conditions.
a. Verify vent pipe is cool to the touch.
b. Disconnect power to furnace and remove vent connector from
furnace vent elbow.
c. Restore power to furnace and set room thermostat above room
temperature.
d. After normal start-up, allow furnace to operate for 2 minutes,
then block vent elbow in furnace 80 percent of vent area with a
piece of flat sheet metal.
e. Furnace should cycle off within 2 minutes. If gas does not shut
off within 2 minutes, determine reason draft safeguard switch did
not function properly and correct condition.
f. Remove blockage from furnace vent elbow.
g. Switch will auto-reset when it cools.
h. Re-install vent connector.
NOTE: Should switch remain open longer than 3 minutes, furnace
control board will lockout the furnace for 3 hours. To reset furnace
control board, turn thermostat below room temperature or from HEAT to
OFF and turn 115-V power OFF, then back ON.
3. Check Pressure Switch
This control proves operation of the draft inducer blower.
a. Turn off 115-V power to furnace.
b. Disconnect inducer motor lead wires from wire harness.
c. Turn on 115-V power to furnace.
d. Set thermostat to “call for heat” and wait 1 minute. When
pressure switch is functioning properly, hot surface igniter
should NOT glow and control diagnostic light flashes a status
CAUTION
!
FURNACE DAMAGE HAZARD
Failure to follow this caution may result in:
- Overheating the heat exchangers or condensing flue gases in
heat exchanger areas not designed for condensate.
- Shortened furnace life
- Component damage.
Temperature rise must be within limits specified on furnace rating plate.
Recommended operation is at midpoint of rise range or slightly above.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Blower access door switch opens 115-V power to control. No
component operation can occur unless switch is closed. Caution must
be taken when manually closing this switch.
WARNING
!
FIRE HAZARD
Failure to follow this warning could result in personal injury, death,
and/or property damage.
Reinstall manifold pressure tap plug in gas valve to prevent gas leak.
WARNING
!
FURNACE OVERHEATING HAZARD
Failure to follow this caution may result in reduced furnace life.
Recheck temperature rise. It must be within limits specified on the
rating plate. Recommended operation is at the mid-point of rise range
or slightly above.
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