C L I M A T E M A S T E R W A T E R - S O U R C E H E A T P U M P S
Rooftop (TRE) Series
R e v. : O c t o b e r 7 , 2 0 1 9
30
C l i m a t e M a s t e r Wa t e r - S o u r c e H e a t P u m p s
ClimaDry
®
II Sequence of Operation
Table 2: Humidistat/Dehumidistat Logic and DXM2 (2.1, 2.2., 2.3) DIP settings
Sensor
2.1
2.2
2.3
Logic
Reheat (ON)–H
Reheat (OFF)–H
Humidistat
OFF
OFF
OFF
Reverse
0 VAC
24 VAC
Dehumidistat
OFF
ON
OFF
Standard
24 VAC
0 VAC
1
Cooling input takes priority over dehumidify input.
2
DXM2 is programmed to ignore the H demand when the unit is in heating mode.
3
N/A for single stage units; Full load operation for dual capacity units.
4
ON/OFF = Either ON or OFF.
Mode
Input
Output
O
G
Y1
Y2
3
H
O
G
Y1
Y2
3
Reheat
No Demand
ON/OFF
OFF
OFF
OFF
OFF
ON/OFF
OFF
OFF
OFF
OFF
Fan Only
ON/OFF
ON
OFF
OFF
OFF
ON/OFF
ON
OFF
OFF
OFF
Cooling 1st Stage
ON
ON
ON
OFF
OFF
ON
ON
ON
OFF
OFF
Cooling 2nd Stage
ON
ON
ON
ON
OFF
ON
ON
ON
ON
OFF
Cooling & Dehumidistat
1
ON
ON
ON
ON/OFF
ON
ON
ON
ON
ON/OFF
OFF
Dehumidistat Only
ON/OFF
OFF
OFF
OFF
ON
ON
ON
ON
ON
ON
Heating 1st Stage
OFF
ON
ON
OFF
OFF
OFF
ON
ON
OFF
OFF
Heating 2nd Stage
OFF
ON
ON
ON
OFF
OFF
ON
ON
ON
OFF
Heating & Dehumidistat
2
OFF
ON
ON
ON/OFF
ON
OFF
ON
ON
ON/OFF
OFF
Table 3: ClimaDry
®
II Operating Modes
ClimaDry
®
II Sequence of Operation
-
A heat
pump equipped with ClimaDry
®
II can operate in three
modes; cooling, cooling with reheat (dehumidification),
and heating. The cooling/heating modes are like
any other ClimateMaster WSHP. The reversing valve
(“O” signal) is energized in cooling, along with the
compressor contactor(s) and blower relay. In the heating
mode the reversing valve is de-energized. Almost any
thermostat will activate the heat pump in heating or
cooling modes. The DXM2 microprocessor board, which
is required with the ClimaDry
®
II option, will accept
either heat pump (Y,O) thermostats or non-heat pump
(Y,W) thermostats. The reheat mode requires either
a separate humidistat/dehumidistat or a thermostat
that has an integrated dehumidification function for
activation. The DXM2 board is configured to work with
either a humidistat or dehumidistat input to terminal
“H” (DIP switch settings for the DXM2 board are shown
below in table 2). Upon receiving an “H” input, the
DXM2 board will activate the cooling mode and engage
reheat. Tables 1 and 2 show the relationship between
thermostat input signals and unit operation. There are
four operational inputs for single stage units and six
operational inputs for dual stage units:
-Fan Only
-1st Stage Cooling
-2nd Stage Cooling
-1st Stage Heating
-2nd Stage Heating
-Reheat Mode
• Fan Only: A (G) call from the thermostat to the (G)
terminal of the DXM2 control board will bring the unit
on in fan only mode.
• 1st Stage Cooling: A simultaneous call from (G),
(Y1), and (O) to the (G), (Y1), (O/W2) terminals of the
DXM control board will bring the unit on in 1st Stage
Cooling.
• 2nd Stage Cooling: A simultaneous call from (G),
(Y1), (Y2), and (O) to the (G), (Y1), (Y2), and (O/
W2) terminals of the DXM2 control board will bring
the unit on in 2nd Stage Cooling. When the call is
satisfied at the thermostat the unit will continue to
run in 1st Stage Cooling until the 1st Stage Cooling
call is removed or satisfied, shutting down the
unit.
NOTE: Not all units have two-stage cooling
functionality.
