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Installation, Operation & Maintenance - HKV Series
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
Table 2: Humidistat/Dehumidistat Logic and DXM2 (2.1, 2.2, 2.3) DIP Settings
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
Comfort-Aire/Century 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 eitherv 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”. Upon receiving an
“H” input, the DXM2 board will activate the cooling
mode and engage reheat. Table 4 shows 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
DXM2 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.
• 1st Stage Heating: A simultaneous call from (G) and (Y1)
to the (G) and (Y1) terminals of the DXM2 control board
will bring the unit on in 1st Stage Heating.
• 2nd Stage Heating: A simultaneous call from (G),
(Y1), and (Y2) to the (G), (Y1), and (Y2) terminals of the
DXM2 control board will bring the unit on in 2nd Stage
Heating. When the call is satisfied at the thermostat
the unit will continue to run in 1st Stage Heating until
the call is removed or satisfied, shutting down the
unit.
NOTE: Not all units have two-stage heating
functionality (e.g. HKV084-150 units).