Trane PTEC-070 Operation & Maintenance Manual page 13

WARNING!
Hazardous Voltage!
Disconnect all electric power,
including remote disconnects before
servicing. Follow proper lockout/
tagout procedures to ensure the
power can not be inadvertently
energized. Failure to disconnect
power before servicing could result
in death or serious injury.
Master Switch
The master switch disconnects
power to all of the system
components. When this switch is in
the off position, the compressor, fan
motor, reversing valve, and electric
resistance heater will all be de-
energized.
Remote/ Standard Switch
The remote/standard switch is used
to change the control of the unit
from the standard on board controls
in the standard mode, to a remote
wall mounted thermostat in the
remote mode. For remote
thermostat operation refer to
Remote Operation section.
PTEC-M-1A
Chassis
Information
Fan Cycle Switch
The fan cycle switch sets the
operational mode of the fan. In the
ON position, the fan will run
continuously whenever the unit is in
the heat or cool mode. In the AUTO
position, the fan will cycle on and off
with the compressor or electric
heater when the unit is in the cool or
heat mode.
Remote Control Inputs
The C, R, GH, GL, W2, Y/W1 and B
terminals provide control inputs for a
remote wall mounted thermostat.
For remote control operation refer to
Remote Thermostat Operation
section.
Front Desk Control
The FD1 and FD2 terminals provide
control inputs for a front desk switch.
Shorting across these two terminals
will disable unit operation. The only
control function which will remain
active when these terminals are
shorted is freeze protection. Any
Front Desk Switch Wiring Schematic
IMPORTANT NOTE: Do not apply 24VAC across these terminals. Applying
24VAC to these terminals will result in failure of the control board. Shorting
these terminals to any other terminals may also result in control board failure.
switch which will produce a short
circuit across these two terminals
can be used as a front desk switch.
The contact resistance of the switch,
when closed, must be less than 200
ohms for the front desk feature to
operate properly.
The following table shows the
maximum wire length and
corresponding gauge size for
installation of a front desk switch.
Maximum Wire Length
For Front Desk Switch
Wire Size Maximum Length
(AWG) Allowed
#24 400 ft
#22 600 ft
#20 900 ft
#18 1500 ft
#16 2000 ft
The figure below shows a wiring
schematic for connecting the front
desk switch to the unit.
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