C L I M AT E M A S T E R WAT E R - S O U R C E H E AT P U M P S
TSM/TSL Vertical Stack
R e v. : J a n u a r y 1 8 , 2 0 2 1
C l i m a t e M a s t e r Wa t e r-S o u rc e H e a t P u m p s
54
JW3 should never be clipped for equipment or systems
without correct antifreeze mixture.
⚠
NOTICE!
⚠
CXM PCB
LT1
LT2
LT1
LT1
LT2
LT2
JW3-LT1 jumper
should be
clipped for low
temperature
operation
Electrical Wiring – Low Voltage
Figure 13: LT1 Limit Setting
Thermostat Connections -
The thermostat can be spliced
or wired directly to the CXM or DXM2 board. See Unit
Wire Diagram. Review the appropriate thermostat AOM
(Application, Operation and Maintenance) manual.
Wall Sensors (ASW) for MPC or LON -
Connections are
made to DDC controller, see Unit Wire Diagram.
Cabinets with MPC or LON (model digit 5 is C,D,L,M, 2,
or 3) requires field to clip JW1 jumper on CXM or DXM2
board in chassis.
Low Water Temperature Cutout Selection -
The CXM/
DXM2 control allows the field selection of low water (or
water-antifreeze solution) temperature limit by clipping
jumper JW3, which changes the sensing temperature as-
sociated with thermistor LT1. Note that the LT1 thermistor
is located on the refrigerant line between the coaxial heat
exchanger and expansion device (TXV). Therefore, LT1 is
sensing refrigerant temperature, not water temperature,
which is a better indication of how water flow rate and
temperature is affecting the refrigeration circuit.
The factory setting for LT1 is for systems using water
no lower than 50ºF (10ºC), boiler tower or open loop.
Water temperature below 50ºF (10ºC) (extended range)
applications must use antifreeze (most ground loops),
jumper JW3 must be clipped as shown in Figure 13.
Lowest refrigerant temperature, LT1 can sense without
faulting off is, with LT1 unclipped - 30ºF (-1ºC) and
clipped - 10ºF (-12ºC). All ClimateMaster units operating
with entering water temperatures below 59°F [15°C]
must include the optional water/refrigerant circuit
insulation package to prevent internal condensation.