System information
ClimateMaster Geothermal Heat Pump Systems
33
Residential Products Technical Guide
Figure 22: Example Size 030 Performance
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 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 DXM
microprocessor board, which is standard with the ClimaDry
®
II
option, will accept either heat pump (Y,O) thermostats or non-
heat pump (Y,W) thermostats (see DXM AOM for detailed DXM
information).
The reheat mode requires either a separate humidistat/
dehumidistat or a thermostat that has an integrated
dehumidifi cation function for activation. The DXM board is
confi gured to work with either a humidistat or dehumidistat
input to terminal “H” (DIP switch settings for the DXM board are
shown below in table 5). Upon receiving an “H” input, the DXM
board will activate the cooling mode and engage reheat. Table 6
shows the relationship between thermostat input signals and unit
operation.
There are fi ve operational inputs for single stage units and seven
operational inputs for two stage units:
-Fan Only
-1st Stage Cooling
-2nd Stage Cooling
-1st Stage Heating
-2nd Stage Heating
-3rd Stage Heating (If applicable)
-Reheat Mode
•
Fan Only: A (G) call from the thermostat to the (G) terminal of
the DXM 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 DXM
control board will bring the unit on in 2nd Stage Cooling. When
the call is satisfi ed at the thermostat the unit will continue to run
in 1st Stage Cooling until the 1st Stage Cooling call is removed or
satisfi ed, 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 DXM control board will bring the
unit on in 1st Stage Heating.
Table 5: Humidistat/Dehumidistat Logic and DXM (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
ClimaDry
®
II
°
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°
°
°
°
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Dividing the latent capacity by 1,069 BTU/LB of water vapor at 80°F DB and 67°F WB [26.7°C DB and 19.4°C WB] moist air enthalpy, converts the amount
of moisture removal to pounds per hour (multiply pounds per hour by 0.4536 to obtain kg/hr). Calculations are shown in fi gure 22.