Am7 Sequence Of Operation; Abbreviations; Continuous Fan; Heatpump Od Single Stage (Heating Mode) - Trane 7 Series Field Reference Data

SEQUENCE OF OPERATION FOR *AM7 AIR HANDLERS

AM7 Sequence of Operation

Abbreviations

• AFC = Airflow Control
• EVC = Expansion Valve Control
• EEV = Electronic Expansion Valve
• EHC = Electric Heat Control
• YI = Y signal from the comfort control
• YO = Y signal out of the AFC from the comfort control
• Y2 = Y2 signal from comfort control
This unit has unique a feature that receives 24VAC analog
inputs from a conventional comfort control and then
converts these inputs to serial communicating signals
between the different controls within the air handler.
The installing and servicing technician should have an
understanding of the sequence of operation to be able
to properly setup and diagnose functions of the air
handler.
The dip switch settings on the control boards must be prop-
erly set to obtain the correct sequence of operation.
Reference the air handler and electric heat wiring dia-
grams and dip switch configuration chart for additional
information.
See unit, electric heat, and field wiring diagrams for ad-
ditional information.

Continuous Fan

IMPORTANT: If the indoor air exceeds 60% relative
humidity or simply feels uncomfortably humid, it
is recommended that the indoor fan only be used
in the AUTO mode.
1. R-G contacts close on comfort control sending 24VAC
to the G terminal of the AFC.
2. The AFC micro-processor sends a command to the
serial communicating blower motor to run at 50%.
See airflow Dip Switch settings for additional info.

Heatpump OD Single Stage (heating mode)

1. R-Y contacts close on the comfort control sending
24VAC to Y1 terminal on the AFC.
2. Normally closed contacts on the AFC will pass 24VAC
to the YO terminal providing power to the outdoor unit
control circuit.
3. R-G contacts close on comfort control sending 24VAC
to the G terminal of the AFC.
4. The AFC micro-processor sends a command to the
serial communicating blower motor to run at 100%.
Heatpump OD Two Stage (heating mode)
1. R-Y1 contacts close on the comfort control sending
24VAC to Y1 terminal on the AFC.
2. Normally closed contacts on the AFC will pass 24VAC
to the YO terminal providing power to the outdoor unit
1st stage control circuit.
3. R-G contacts close on comfort control sending 24VAC to
the G terminal of the AFC.
4. The AFC micro-processor sends a command to the serial
communicating blower motor to run at 1st stage heating
cfm.
5. R-Y2 contacts close on the comfort control sending
24VAC to Y2 terminal on the AFC.
6. The Y2 signal is also passed through to provide power to
the outdoor unit 2nd stage control circuit.
7. The blower motor will now run at 100% of the heating
cfm.
OD Single Stage (cooling mode)
1. R-Y contacts close on the comfort control sending
24VAC to Y1 terminal on the AFC.
2. Normally closed contacts on the AFC will pass 24VAC
to the YO terminal providing power to the outdoor unit
control circuit.
a. Heatpump OD = R-O contacts close on the comfort
control sending 24VAC to the O terminal of the AFC.
The AFC communicates to the EVC that the system is in
cooling mode. The O signal is passed through to the OD
unit.
b. Non heatpump OD = OD dip switch configuration will
communicate to the EVC to control superheat on a Y
only signal.
3. R-G contacts close on comfort control sending 24VAC to
the G terminal of the AFC.
4. The AFC micro-processor sends a command to the serial
communicating blower motor to run at 100% of the cool-
ing cfm.
5. The EVC will receive input from the two temperature sen-
sors and start to control superheat.
OD Two Stage (cooling mode)
1. R-Y1 contacts close on the comfort control sending
24VAC to Y1 terminal on the AFC. The AFC communi-
cates to the EVC to control superheat for 1st stage.
2. Normally closed contacts on the AFC will pass 24VAC to
the YO terminal providing power to the outdoor unit 1st
stage control circuit.
a. Heatpump OD = R-O contacts close on the comfort
control sending 24VAC to the O terminal of the AFC.
The AFC communicates to the EVC that the system is in
cooling mode. The O signal is passed through to the OD
unit.
b. Non heatpump OD = OD dip switch configuration will
communicate to the EVC to control superheat on a Y
only signal.
3. R-G contacts close on comfort control sending 24VAC to
the G terminal of the AFC.
4. The AFC micro-processor sends a command to the se-
rial communicating blower motor to run at the 1st stage
cooling cfm. (1st stage cooling cfm is a multiplier of 2nd
stage cfm)
5. The EVC will receive input from the two temperature sen-
sors and start to control 1st stage superheat.
TAM7­4