59TP6C: 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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radiant heat does not affect readings. This practice is particularly
important with straight-run ducts.
2. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine air
temperature rise.
NOTE: The temperatures read by the RAT and SAT sensors connected
to the control board can be displayed during heating and cooling
operation by enabling this feature in the (t°) menu item. See Fig. 59.
Select F for Fahrenheit or C for Celsius. When enabled, the display will
cycle through the current operating mode, SAT, RAT, and temperature
differential. If displayed SAT value does not agree with measured
values, relocate SAT sensor farther away from furnace or after a bend in
the ductwork.
NOTE: Temperature rise can be determined for low-heat and high-heat
operation by locking the furnace in each mode of operation. The mode of
operation is based on the (Htt) setting on the furnace control board.
3. If temperature rise is outside this range, proceed as follows:
a. Check gas input for low- and high-heat operation.
b. Check derate for altitude, if applicable.
c. Check all return and supply ducts for excessive restrictions
causing static pressure greater than 0.5 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. 59. and Fig. 60
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 low 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)
to depending on thermostat type. See Fig. 59. and Fig. 60.
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 the temperature limit control, it can be established
that the limit is functioning properly and that the limit will operate
if there is a restricted return-air supply or motor failure. If the limit
control does not function during this test, the 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 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 low
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, determine reason
pressure switch did not function properly and correct condition.
e. Turn off 115-V power to furnace.
f. Reconnect inducer motor wires, replace door, and turn on 115-V
power.
g. Blower will run for 90 sec before beginning the call for heat
again.
h. Furnace should ignite normally.
Checklist
• Put away tools and instruments. Clean up debris.
• Check Input/Output gas pressure
• Check heat rise per application static pressure
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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