Trane TCONT900AC43UA - Indoor Blower Motor Operation Thermostat Fan Switch CONTINUOUS

GF - A 5
Furnace Sequences Of Operation
24VAC Mode
1
8
4b 4d4c
5a
5c
6a 6b
9
7
10
3
4a
5b
2a2b2c 2d
18. The IFC receives a 24 VAC signal from PS1 and PS2
when they close. This verifies the vent motor is moving
the correct amount of combustion air through the furnace and
the vent system.
19. IFC starts the hot surface ignitor learning routine
warm-up time cycle.
20. IFC turns on the gas valve. Trial time for ignition is 5
seconds.
21. The IFC verifies ignition by the flame current sensing
method. If a flame is not detected, the IFC will cycle the
furnace three times to try and verify a flame. If no flame is
detected, the IFC will lockout for one hour. The IFC will send an
alert code to the User Interface as well as flash its Red alert
LED two times repeatedly.
22. If a flame is detected, the IFC will start the heat exchanger
warm-up time delay for the indoor blower.
23. “IGNITION” will now be displayed in the “STATUS” section of
the User Interface menu.
24. After 45 seconds, the IFC signals the indoor blower
motor to run at the programmed ignition sequence speed.
25. Every 1 minute, the IFC will signal the vent motor to
ramp up. The increase of the vent motor speed allows the gas
flow through the gas valve to also be increased in 3% steps.
This 3% increase will be repeated every 1 minute until the
capacity requested is 100%. Pressure switch 3 closes at
approximately 95% of capacity.
26. The IFC will also increase the indoor blower motor speed
in appropriate steps. (The interstage delay is field selectable and
can be adjusted through the User interface menu. It is factory
set at 0 minutes but can be adjusted to 5, 10, or 15 minutes.) This
option can help optimize the furnace to try to satisfy the heating
requirement during low heating load conditions.
Indoor Blower motor operation thermostat fan switch
“CONTINUOUS”
R and G comfort control contacts close signaling a
continuous fan call. The continuous fan cfm is field selectable
and can be adjusted through the User Interface menu. The
factory setting is 50% of the cooling cfm selected but can be
set at 25%, 50%, 75%, or 100%. If the system has a 2 stage
outdoor unit, the setting is 50% of the 2nd stage cooling cfm.
Note:
The furnace lights at approximately 65% of capacity.
3
5a
5b
7
8
1
5c
2a 2d
3
3
3
9
1
3
10
10
3
6b
6b
8
3 10
1
1
*