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8
cP/BP series
tHerMostat coNNectioNs
Thermostat wiring is connected to a 7 position low
voltage terminal block in the electrical box. The
thermostat connections and their functions are as
follows:
y
Compressor Operation
G Fan
o Reversing Valve (energized in cooling)
c
Transformer 24 VAC Common – 3 Connections
r
Transformer 24 VAC Hot
If the unit is being connected to a thermostat with a
malfunction light, this connection is made at the
unit alarm output.
If the thermostat is provided with a malfunction
light powered off of the common (C) side of the
transformer, a jumper between "R" and "COM"
terminal of "ALR" contacts must be made.
If the thermostat is provided with a malfunction
light powered off of the hot (R) side of the
transformer, then the thermostat malfunction light
connection should be connected directly to the
(ALR) contact on the unit's UPM board.
saFety deVices aNd tHe
uPM coNtroller
Each unit is factory provided with a Unit Protection
Module (UPM) that controls the compressor opera-
tion and monitors the safety controls that protect
the unit.
Safety controls include the following:
• High pressure switch located in the refrigerant
discharge line and wired across the HPC
terminals on the UPM
• Low pressure switch located in the unit
refrigerant suction line and wired across
terminals LPC1 and LPC2 on the UPM.
• Optional freeze protection sensor, mounted close
to condensing water coil, monitors refrigerant
temperature between condensing water coil and
thermal expansion valve. If temperature drops
6 720 220 045
below or remains at freeze limit trip for 30
seconds, the controller will shut down the
compressor and enter into a soft lockout
condition. The default freeze limit trip is 30°F,
however this can be changed to 15°F by cutting
the R42 resistor located on top of DIP switch SW1.
• The optional condensate overfl ow protection
sensor (standard on horizontal units) is located in
the drain pan of the unit and connected to the
'COND' terminal on the UPM board.
Caution
Subject to change without prior notice
thermostat connections
If freeze protection sensor is not installed, a
jumper between freeze contacts must be installed
on the UPM board otherwise unit will not start.
Freeze
Protection
Sensor
Revised 05-12
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