23
Residential Packaged Units - 60Hz Puron
®
Rev.: 4 Jan., 2012
Electrical - Thermostat Wiring
Figure 24: Units With Optional ECM Fan.
Figure 25: Typical Thermostat 2 Heat/1 Cool (PSC Fan)
Thermostat Installation
The thermostat should be located on an interior wall in a
larger room, away from supply duct drafts. DO NOT locate
the thermostat in areas subject to sunlight, drafts or on
external walls. The wire access hole behind the thermostat
may in certain cases need to be sealed to prevent erroneous
temperature measurement. Position the thermostat back
plate against the wall so that it appears level and so the
thermostat wires protrude through the middle of the back
plate. Mark the position of the back plate mounting holes
and drill holes with a 3/16” (5mm) bit. Install supplied
anchors and secure plate to the wall. Thermostat wire must
be 18 AWG wire. Wire the appropriate thermostat as shown
in Figures 24 and 25 to the low voltage terminal strip on the
CXM (units with PSC motor) or ECM control board (units
with ECM motor). Practically any heat pump thermostat will
work with these units, provided it has the correct number of
heating and cooling stages.
ATM21U01 Thermostat
Connection to CXM Control
Compressor
Heating Stage 2
Reversing Valve
Fan
24Vac Hot
24Vac Common
Fault LED
Y
Y2/W
O
G
R
C
L
Y
W
O
G
R
C
AL1
CXM
NOTICE: Units with Whole House Dehumidifi cation whole
house dehumidifi cation option require a separate humidistat
or thermostat part number ATP32U04 (See Whole House
Dehumidifi cation AOM for more details).
ATP32U04 Thermostat
Connection to ECM Control
Compressor
Compressor Stage 2
Reversing Valve
Fan
24Vac Hot
24Vac Common
Fault LED
ECM
Board
Y1
Y2
W
DH
O
G
R
C
AL1
Y1
Y2
W
DH
O
G
R
C
L
Dehumidification
Units with CXM or DXM board and ECM fan motor, utilizing ECM dehumidification
mode (without ClimaDry option)
Notes:
1) Units with whole house dehumidification option have slightly different
thermostat wiring.Terminal DH at the thermostat is connected to terminal H at
the DXM board
2) ECM dehumidification mode slows down fan speed in the cooling mode when
dehumidification output from thermostat is active. Normal heating and cooling fan
speeds are not affected.
3) ECM board DIP switch SW9 must be in dehumid. mode for
ECM dehumidification mode.
Auxiliary Heat
6
CAUTION!
CAUTION! Many units installed with a factory or fi eld
supplied manual or electric shut-off valve. DAMAGE WILL
OCCUR if shut-off valve is closed during unit operation. A
high pressure switch must be installed on the heat pump
side of any fi eld provided shut-off valves and connected to
the heat pump controls in series with the built-in refrigerant
circuit high pressure switch to disable compressor
operation if water pressure exceeds pressure switch setting.
The fi eld installed high pressure switch shall have a cut-out
pressure of 300 psig and a cut-in pressure of 250 psig. This
pressure switch can be ordered with a 1/4” internal fl are
connection as part number 39B0005N02.
CAUTION!
CAUTION! Refrigerant pressure activated water regulating
valves should never be used with this equipment.
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