System information

ManualsBrandsComfort Line Product ManualsHeating SystemSTG-1

Geothermal Applications

ClimateMaster: Smart. Responsible. Comfortable.

ClimaDry

II is a simple and easy to troubleshoot refrigerant

circuit. No switching valves or hard to diagnose leaky check valves

are utilized. No unusual refrigerant pressures occur during the

reheat mode. The ClimaDry

II refrigerant circuit is like every

other ClimateMaster unit (without reheat), so everything the

technician already knows applies to troubleshooting the ClimaDry

II refrigeration circuit. Plus, the water loop portion of the

ClimaDry

II option is easy to understand and diagnose.

Features Include:

• Modulating reheat for precise control of supply

air temperatures

• 100% reheat (operates as a dehumidiﬁ er)

• “Neutral” supply air temperature even at part load (non-

design) conditions

• Supply air temperature adjustment, +/- 3°F [+/-1.7°C] from

72°F [22°C] factory setpoint with optional potentiometer

• Integrated reheat controls – simply attach a humidistat

or dehumidistat

• Microprocessor (DXM) controls standard

• Ultra simple refrigeration circuit

• All water system eliminates refrigeration circuit modiﬁ cations

(same refrigeration circuit as units without ClimaDry

II)

• Stable refrigeration pressures, even at low EWTs

• All components located inside the cabinet

•

Moves heat of rejection from ground loop to supply air stream

Availability

ClimaDry

II is currently available on ClimateMaster vertical and

horizontal residential Tranquility

30 (TT) and Tranquility

20 (TS)

series units.

ClimaDry

II Applications

With the ClimaDry

II option, return air from the space is

conditioned by the air-to-refrigerant (evaporator) coil, then

reheated by the water-to-air (reheat) coil to dehumidify the air,

but maintain the same space temperature (thus operating as a

dehumidiﬁ er). The moisture removal capability of the heat pump

is determined by the unit’s latent capacity rating. Latent Capacity

(LC) equals Total Capacity (TC) minus Sensible Capacity (SC). For

example, at 85°F [29°C] EWT, the moisture removal capability

(latent capacity) of a ClimateMaster size 036 heat pump is 9.6

MBtuh [2.8kW] as shown in Table 4.

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. Most ClimateMaster

heat pumps have a sensible-to-total (S/T) ratio of 0.72 to 0.76.

Therefore, approximately, 25% of the cooling capacity is dedicated

to latent cooling capacity (moisture removal). When selecting a

unit with ClimaDry

II, the space sensible and latent loads should

be calculated. If the unit will be used for space cooling, a unit

with at least enough capacity to satisfy the building sensible load

should be selected. If the latent cooling load is not satisﬁ ed by the

selection, a larger unit with enough latent capacity will be required.

The ClimaDry

II option can be used for the additional moisture

load. If the unit will be used for dehumidiﬁ cation purposes only,

the latent capacity is the only consideration necessary. In this case,

sensible load is immaterial. Example latent capacities for a typical

ClimateMaster heat pump are shown in table 4.

ClimaDry

II is especially useful in Northern Climates, where

the heat pump may be oversized in cooling to provide enough

heating. Units with ClimaDry

II will compensate for these

applications by operating as a whole house dehumidiﬁ er when

necessary to maintain space RH.

Since the ClimaDry

II option is internal to the unit, installation is

much easier than a separate whole house dehumidiﬁ er. Plus, an

additional compressor and controls can be eliminated, simplifying

the system and lowering operating and installation costs.

Table 4: Typical Unit Latent capacity

Latent Capacity at 85°F [29.4°C] EWT

Size MBtuh lbs/hr kW kg/hr

18 4.7 4.4 1.4 2.0

24 6.1 5.7 1.8 2.6

30 6.8 6.4 2.0 2.9

36 9.6 9.0 2.8 4.1

42 11.0 10.3 3.2 4.7

48 12.7 11.9 3.7 5.4

60 15.2 14.2 4.5 6.4

70 16.9 15.8 5.0 7.2

ClimaDry