835966-UIM-E-0814
Johnson Controls Unitary Products
9
DEHUMIDIFICATION CONTROL (Typical)
The indoor unit Installation Manual instructions for the air handler or fur-
nace describe the interface with the outdoor heat pump. A dehumidifi-
cation control accessory 2HU16700124 may be used with variable
speed air handlers or furnaces in high humidity areas. This control
works with the variable speed indoor unit to provide cooling at a
reduced air flow, lowering evaporator temperature and increasing latent
capacity. The humidistat in this control opens the humidistat contacts as
the humidity rise. Installation instructions are packaged with the acces-
sory. (Also see Figures 10 - 20). Prior to the installation of the dehumid-
ification control, the humidistat jumper must be set to ‘YES” on the
indoor variable speed air handler or furnace control board.
During cooling, if the relative humidity in the space is higher than the
desired set point of the dehumidification control, the variable speed
blower motor will operate at lower speed until the dehumidification con-
trol is satisfied. A 40-60% relative humidity level is recommended to
achieve optimum comfort.
If a dehumidification control is installed, it is recommended that a mini-
mum air flow of 325 cfm/ton be supplied at all times.
To see connection diagrams of all UPG equipment, the “Low Voltage
System Wiring” document is available online at www.upgnet.com in the
Product Catalog Section.
INDOOR CUBIC FEET PER MINUTE (CFM) CONFIGU-
RATION (Typical)
For proper system operation, the indoor CFM must be set properly.
Refer to the Technical Guide of the outdoor unit for the recommended
air flow settings of each size condensing unit and matching indoor unit.
Set the cooling speed per the instructions for the air handler or furnace.
Verify the airflow.
If installed as a communicating system (outdoor, indoor, and thermo-
stat), the system will automatically adjust to the optimal airflow settings.
These parameters can also be modified using the Touch Screen Com-
munication Control. Refer to the Touch Screen Communication Control
owner’s manual for this procedure. Manual setting of the airflow jump-
ers on the indoor equipment is not necessary with the Touch Screen
Communication Control.
Do not place more than one wire under any single communication
terminal screw (there are four communication terminal screws). If
more than one wire must be connected to a terminal screw, attach
only the terminal end of a one wire pigtail no longer than 6“, and
use a wire connector to connect the other end of the pigtail to the
other wires. Failure to do this will result in nuisance communication
error faults. See Figure 9.
FIGURE 9:
Multi-wire Terminal Connection
WIRE
CONNECTOR
THERMOSTAT
OUTDOOR UNIT
A+
R
C
B-
TERMINAL
SCREW
INDOOR UNIT
NOTE
ENSURE ONLY ONE WIRE UNDER
TERMINAL SCREW.
TO CONNECT MORE THAN ONE WIRE:
1. CONNECT ONLY TERMINAL END OF
6” WIRE PIGTAIL.
2. USE WIRE CONNECTOR TO CONNECT
OTHER END OF PIGTAIL TO OTHER
WIRES.
A020-001
