835959-UIM-D-0814
8
Johnson Controls Unitary Products
6.
Route the 24-volt control wiring (NEC Class 2) from the outdoor
unit to the indoor unit and thermostat.
DEHUMIDIFICATION CONTROL (Typical)
A dehumidification 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 on
humidity rise. To install, refer to instructions packaged with the acces-
sory and Figures 6 & 7. Prior to the installation of the dehumidification
control, the humidistat jumper must be set to “YES”.
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) SELEC-
TION BOARD SETTINGS (Typical)
For proper system operation the CFM Selection Board jumpers must be
set properly.
Refer to the Tabular Data Sheet for the recommended air flow settings
for each size condensing unit.
Set the cooling speed per the instructions for the air handler or furnace
by selecting the correct COOL and ADJUST (or ADJ) taps. Verify the
airflow using the LED display on the CFM selection board.
The HEAT PUMP jumper
MUST
be placed on “YES” or “HP” (depend-
ing on which control board is present) for proper system operation.
The HUMIDISTAT jumper must be placed on “YES” if a dehumidistat is
installed.
SECTION VIII: SYSTEM START-UP
ENERGIZE CRANKCASE HEATER
In order to energize the crankcase heater, set the indoor cooling ther-
mostat to the OFF position. Close the line power disconnect to the unit.
WITH POWER TO UNIT AND THERMOSTAT IN COOLING POSI-
TION:
1.
In the cooling cycle, discharge gas is pumped to the outdoor coil
which is the condenser. The indoor coil is the evaporator.
2.
If fan switch is in the ON position, a circuit is made through blower
relay to provide continuous blower operation.
3.
With fan switch is in the AUTO position, a circuit is made from ther-
mostat cooling contact through blower relay to provide blower
operation.
4.
System will cycle with thermostat demand to provide cooling as
needed.
To eliminate erratic operation, seal the hole in the wall at the thermo-
stat with permagum or equivalent to prevent air drafts affecting the
operation of in the thermostat.
A Start Assist Kit is available and recommended for long line set
applications or in areas of known low voltage problems.
NOTICE
FIGURE 6:
CFM Selection Board
An attempt to start the compressor without at least 8 hours of
crankcase heat will damage the compressor.
CFM SELECTION BOARD
TAP SELECTION
D
C
B
A
D
C
B
A
COOL
HEAT
ADJ
DELAY
REMOVE FOR
HEAT PUMP
HUMIDISTAT
A0196-001
