Adjust Continuous Fan Airflow (And Low-Speed Cooling Airflow); Adjust Thermostat Heat Anticipator; Check Safety Controls; Checklist - Carrier 59TN6A Installation, Start-Up, Operating And Service And Maintenance Instructions

ii
NOTE: The airflow selected via SW3 (Low-Speed Cooling
Airflow) cannot exceed the airflow selected via SW2 (High-Speed
Cooling Airflow). For other CFM per ton Setup switch selections,
see Fig. 35 and Fig. 55.
NOTE: The airflow settings for SW2 and SW3 selections are the
same, EXCEPT for the default values. See Table 7.
For a complete explanation of cooling airflow, refer to the section
titled "Sequence of Operation."
Adjust Continuous Fan Airflow (and Low-Speed
Cooling Airflow)
NOTE: When the furnace is used with a 2-speed cooling or heat
pump unit, the airflow selected for continuous fan via Setup switch
SW3 will also be the airflow used for low-speed cooling, and vice
versa. The continuous fan speed can be further adjusted at a
conventional thermostat using the continuous fan speed select
function. Changing the continuous fan speed at a conventional
thermostat DOES NOT change the low-speed cooling airflow
selected via SW3 at the control board.
NOTE: When the furnace is used with a 2-speed cooling or heat
pump unit, adjust the Continuous Fan CFM Setup switches SW3
to match the airflow required for low-speed cooling.
Select the required continuous fan airflow using Setup switches
SW3 as shown in Fig. 55 and Table 7.
Adjust Thermostat Heat Anticipator.
a. Mechanical thermostat. Set thermostat heat anticipator to
match the amp. draw of the electrical components in the
R-W/W1 circuit. Accurate amp. draw readings can be ob-
tained at the wires normally connected to thermostat sub-
base terminals, R and W. The thermostat anticipator should
NOT be in the circuit while measuring current.
(1.) Set SWl-2 switch on furnace control board to ON.
(2.) Remove thermostat from subbase or from wall.
(3.) Connect an amp. meter as shown in Fig. 53 across
the R and W subbase terminals or R and W wires
at wall.
(4.) Record amp. draw across terminals when furnace is
in low heat and after blower starts.
(5.) Set heat anticipator on thermostat per thermostat
instructions and install on subbase or wall.
(6.) Turn SWl-2 switch OFF.
(7.) Install blower door.
b. Electronic thermostat: Set cycle rate for 3 cycles per hr.
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 lim-
it is functioning properly and will operate if there is a re-
stricted 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 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. If hot surface igniter glows when inducer
motor is disconnected, shut down furnace immediately.
e. Determine reason pressure switch did not function prop-
erly and correct condition.
f. Turn off 115-v power to furnace.
g. Reconnect inducer motor wires, replace door, and turn on
115-v power.
h. Blower will run for 90 sec before beginning the call for heat
again.
i. Furnace should ignite normally.
Checklist
1. Put away tools and instruments. Clean up debris.
2. Verify that switches SWl-1 and SWl-6 are OFF and other
setup switches are set as desired. Verify that switches
SWl-7 and SWl-8 for the blower OFF DELAY are set as
desired per Table 17.
3. Verify that blower and control doors are properly installed.
4. Cycle test furnace with room thermostat.
5. Check operation of accessories per manufacturer's instruc-
tions.
6. Review Owner's Manual with owner.
7. Attach literature packet to furnace.
64