58TN0B/58TN1B: 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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c. Return and supply ducts for excessive restrictions causing static
pressures greater than 0.50-in. w.c.
To lock the furnace in low heat:
1. On the 3 digit display, navigate to (Htt) and select (2St) to lock the
furnace in low-heat operation. See Fig. 45 and Fig. 46.
2. Connect a jumper across R and W/W1 at the thermostat terminals at
the furnace control.
3. Allow the burners to ignite and the blower to turn on.
4. Allow the supply temperature to stabilize and verify the proper rise
range.
If the temperature rise is too high or too low in low heat:
1. Remove jumpers from R and W/W1.
2. Wait until the blower off delay is completed.
3. Remove blower door.
4. Refer to the FURNACE CONTROL PROGRAMMING AND
NAVIGATION section of this manual for instructions on adjusting
the blower speed.
5. Replace blower door.
6. Re-check low heat temperature rise.
To lock the furnace in high heat:
1. Connect a jumper across R and W/W1 and W2 at the thermostat
terminals at the furnace control.
2. Allow the burners to ignite and the blower to turn on.
3. Allow the supply temperature to stabilize and verify the proper rise
range.
If the temperature rise is too high or too low in high heat:
1. Remove jumpers from R and W/W1 and W2.
2. Wait until the blower off delay is completed.
3. Remove blower door.
4. Refer to the FURNACE CONTROL PROGRAMMING AND
NAVIGATION section of this manual for instructions on adjusting
the blower speed.
5. Replace blower door.
6. Re-check high heat temperature rise.
After the temperature rise has been verified:
1. Remove jumpers from thermostat terminals.
2. Allow the blower off delay to complete.
3. On the 3 digit display, navigate to (Htt) and select (1St) or (2St)
depending on thermostat type. See Fig. 45 and Fig. 46.
4. Proceed to “Adjust Blower Off Delay” or install blower door if
complete.
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
This control shuts off combustion 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
return-air supply 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.
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.
f. Remove blockage from furnace vent elbow.
g. Switch will auto-reset when it cools.
h. Re-install vent connector.
3. Check Pressure Switch(es)
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
code (32.2). If hot surface igniter glows when inducer motor is
disconnected, shut down furnace immediately.
e. Determine reason pressure switch did not function properly and
correct condition.
f. Turn off 115-V power to furnace.
g. Reconnect inducer motor wires, replace outer door, and turn on
115-V power.
h. Blower will run for 90 seconds before beginning the call for heat
again.
i. Furnace should ignite normally.
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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