Airflow Adjustment - Trane UC1B040A9241A series Installer's Manual

To check for proper operation of the limit switches, set
the thermostat to a temperature higher than the indi-
cated temperature to bring on the gas valve. Restrict
the airflow by blocking the return air (disconnecting the
indoor blower may trip the inducer limit). When the
furnace reaches the maximum outlet temperature as
shown on the rating plate, the burners must shut off. If
they do not shut off after a reasonable time and over-
heating is evident, a faulty limit switch is probable and
the limit switch must be replaced. After checking the
operation of the limit control, be sure to remove the pa-
per or cardboard from the return air inlet. Refer to Ser-
vice Facts for additional instructions.
NOTE TO INSTALLER
Review the following warnings with the owner. Review
contents of USER'S INFORMATION MANUAL with the
owner.

AIRFLOW ADJUSTMENT

Check inlet and outlet air temperatures to make sure
they are within the ranges specified on the furnace rat-
ing nameplate. If the airflow needs to be increased or
decreased, see the wiring diagram for information on
changing the speed of the blower motor.
▲
WARNING
!
Disconnect power to the unit before removing the
blower door.
Failure to follow this warning could result in property
damage, personal injury or death.
This unit is equipped with a blower door switch which
cuts power to the blower and gas valve causing shut-
down when the door is removed. Operation with the
door removed or ajar can permit the escape of danger-
ous fumes. All panels must be securely closed at all
times for safe operation of the furnace.
INDOOR BLOWER TIMING
Heating: The integrated furnace control module con-
trols the indoor blower. The blower start is fixed at 45
seconds after ignition. The FAN-OFF period is field se-
lectable by dip switches at 60, 100, 140, or 180 seconds.
The factory setting is 100 seconds (See wiring diagram).
Cooling: The fan delay off period is factory set at 0 sec-
onds. The option for 80 second delay off is field select-
able (See wiring diagram).
OOM AIR THERMOSTAT
R
HEAT ANTICIPATOR ADJUSTMENT
Set the thermostat heat anticipator according to the
current flow measured, or the settings found in the
notes on the furnace wiring diagram (found in the SER-
VICE FACTS or inside the furnace casing).
18-CD19D5-25
Installer's Guide
INSTRUCTIONS TO THE OWNERS
In the event that electrical, fuel, or mechanical
failures occur, the owner should immediately
turn the gas supply off at the manual gas valve,
located in the burner compartment. Also turn off
electrical power to the furnace and contact the
service agency designated by your dealer.
BURNER BOX TEMPERATURE LIMIT DEVICE
All models are equipped with a manual reset tempera-
ture limit located on the burner box. In case of exces-
sive temperature, the limit will open and cause the cir-
cuit to open which shuts off all flow of gas.
ABNORMAL CONDITIONS
1. EXCESSIVE COMBUSTION PRESSURE (WIND IN
EXCESS OF 40 M.P.H.) VENT OR FLUE BLOCK-
AGE
If pressure against induced draft blower outlet be-
comes excessive, the pressure switch will open and
shut off the gas valve until acceptable combustion
pressure is again available.
2. LOSS OF FLAME
If loss of flame occurs during a heating cycle, or
flame is not present at the sensor, the flame control
module will close the gas valve. The flame control
module will then recycle the ignition sequence,
then if ignition is not achieved, it will shut off the
gas valve and lock out the system.
3. POWER FAILURE
If there is a power failure during a heating cycle,
the system will restart the ignition sequence auto-
matically when power is restored if the thermostat
still calls for heat.
4. GAS SUPPLY FAILURE
If loss of flame occurs during a heating cycle, the
system integrated control module will recycle the
ignition sequence, then if ignition is not achieved,
the integrated control module will shut off the gas
valve and lock out the system.
5. INDUCED DRAFT BLOWER FAILURE
If pressure is not sensed by the pressure switch, the
contacts will remain open and not allow the gas
valve to open, therefore the unit will not start. If
failure occurs during a running cycle, the pressure
switch contacts will open and the gas valve will
close to shut the unit down.
6. CONDENSATE DRAIN BLOCKAGE
If the condensate drain is blocked, either by debris,
improper draining, or by freezing condensate, the
pressure switch will sense the accumulation of con-
densate in the furnace drain pan. The pressure
switch contacts will open and remain open, not al-
lowing unit operation. The unit will not operate un-
til the condensate drain has been cleared, and the
condensate flows freely.
37