Section 18. Sequence Of Operation - Trane Performance Climate Changer Installation, Operation And Maintenance Manual

Section 18. Sequence of Operation

18.1 Sequence of Operation
AM4 Sequence of Operation
Abbreviations
• EVC = Expansion Valve Control
• EEV = Electronic Expansion Valve
• YI = Y signal into the EVC from the comfort control
• YO = Y signal out of the EVC to the outdoor unit
NOTE: Models with a constant torque motor (5
ton / *AM4A0C60S51SA) do not use blower relay
contacts 1 & 3 to energize the motor. The 24VAC
signal from the G terminal provides the necessary
power to energize the motor.
See unit, electric heat, and field wiring diagrams for ad-
ditional information.
Continuous Fan
1. R-G contacts close on comfort control sending
24VAC to the blower relay
2. Relay contacts 1 and 3 close
3. The blower will now run on the selected speed.
Speed is field selectable
Heatpump OD (cooling)
1. R-Y contacts close on the comfort control sending
24VAC to the YI (Y In) terminal on the EVC.
2. R-G contacts close on comfort control sending
24VAC to the blower relay
3. Relay contacts 1 and 3 close
4. The blower will now run on the selected speed.
Speed is field selectable
5. R-O contacts on the comfort control close sending
24VAC to the O terminal on the EVC. This signals
the EVC that the unit is in cooling mode. The EVC
will control the EEV to maintain the correct super-
heat.
6. Normally closed contacts on the EVC will pass
24VAC to the YO terminal providing power to the
outdoor unit control circuit
Heatpump OD (heating)
1. R-Y contacts close on the comfort control sending
24VAC to the YI (Y In) terminal on the EVC
2. R-G contacts close on comfort control sending
24VAC to the blower relay
3. Relay contacts 1 and 3 close
4. The blower will now run on the selected speed.
Speed is field selectable
5. The combination of 24VAC on the Y terminal and
zero volts on the O terminal signals the EVC that
the unit is in heat-pump heating mode
38
6. Normally closed contacts on the EVC will pass
24VAC to the YO terminal providing power to the
outdoor unit control circuit
Cooling OD
1. R-Y contacts close on the comfort control sending
24VAC to the YI (Y In) terminal on the EVC
2. R-G contacts close on comfort control sending
24VAC to the blower relay
3. Relay contacts 1 and 3 close
4. The blower will now run on the selected speed.
Speed is field selectable
5. R-O jumper on the LVTB sends 24VAC to the O ter-
minal on the EVC. This signals the EVC that the unit
is in cooling mode. The EVC will control the EEV to
maintain the correct superheat
6. Normally closed contacts on the EVC will pass
24VAC to the YO terminal providing power to the
outdoor unit control circuit
Electric Heating
1. R-W contacts close on the comfort control sending
24VAC to the EHC to energize the heat relay.
2. R-G contacts close on comfort control sending
24VAC to the blower relay
3. Relay contacts 1 and 3 close
4. The blower will now run on the selected speed.
Speed is field selectable
5. Contacts 4 & 6 on the blower relay close providing
the interlock circuit to allow the electric heat relays
to operate
The comfort control must be setup to control R-G
contacts with a call for electric heat. This closes the
interlock circuit and allows the heat relay circuit to
be energized.
Optional Condensate Switch
1. An optional OEM condensate switch can be in-
stalled within the unit. This switch is only available
through the National Distribution Center or Global
Parts.
2. Switch contacts are normally open and close when
water level rises. The closed switch will interrupt cur-
rent flow to the YO terminal and de-energize the OD
unit.
3. Switch is only operational during cooling mode. Con-
densate overflow is not operational during heating or
defrost modes.
Standard aftermarket condensate switches cannot be
used within the unit but can be installed exterior of
the unit. The 3rd party condensate overflow switch
must be wired between Y of the thermostat and YI of
the EEV control.