Install Instructions

40
IOM - HZH/HZV Series
ClimaDry II Sequence Of Operation
A heat pump equipped with ClimaDry II can operate in
three modes, cooling, cooling with reheat, 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, 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 8a). Upon receiving an “H”
input, the DXM2 board will activate the cooling mode and
engage reheat. Table 8b 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.
• 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.
• Reheat Mode: A call from the Humidistat/Dehumidistat
to the (H) terminal of the DXM2 control board will
bring the unit on in Reheat Mode if there is no call
for cooling at the thermostat. When the Humidistat
Dehumidification call is removed or satisfied the
unit will shut down. Note: Cooling always overrides
Reheat Mode. In the Cooling mode, the unit cools
and dehumidifies. If the cooling thermostat is satisfied
but there is still a call for dehumidification, the unit will
continue to operate in Reheat Mode.
ClimaDry II Component Functions
The ClimaDry II option consists of the following
components:
• Proportional Controller
• Supply Air Sensor
• Motorized Valve
• Loop Pump
• Hydronic Coil
The Proportional Controller operates on 24 VAC power
supply and automatically adjusts the water valve based
upon the Supply Air Sensor. The Supply Air Sensor
senses supply air temperature at the blower inlet
providing the input signal necessary for the proportional
control to drive the motorized valve during the reheat
mode of operation. The Motorized Valve is a proportional
actuator/three-way valve combination used to divert
the condenser water from the coax to the hydronic
reheat coil during the reheat mode of operation. The
proportional controller sends a signal to the motorized
valve based on the supply air temperature of the supply
air sensor.
ClimaDry II Modulating Reheat Option