835961-UIM-B-0412
8
Johnson Controls Unitary Products
DEHUMIDIFICATION CONTROL
A dehumidification control accessory 2HU06700124 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. Prior to the installation of the dehumidification control, the jumper
across the HUMIDISTAT terminals on the indoor variable speed air han-
dler or furnace CFM selection board must be removed.
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.
For connection diagrams for all UPG equipment refer to “Low Voltage
System Wiring” document available online at www.upgnet.com in the
Product Catalog Section.
CFM SELECTION BOARD SETTINGS
For proper system operation the CFM Selection control 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 ADJ taps. Verify the airflow using
the LED display on the CFM selection board.
SECTION IX: SYSTEM START-UP
ENERGIZE CRANKCASE HEATER
If this unit is equipped with a crankcase heater for the compressor, a
warning label with an adhesive back is supplied in the unit installation
instruction packet. This label should be attached to the field supplied
disconnect switch where it will be easily seen.
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
POSITION:
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 ON position, a circuit is made through blower
relay to provide continuous blower operation.
3.
With fan switch in AUTO position, a circuit is made from thermo-
stat cooling contact through blower relay to provide blower opera-
tion.
4.
System will cycle with thermostat demand to provide cooling as
needed.
FIGURE 9:
Typical Field Wiring (Air Handler / Electrical Heat) (Single-Phase)
THERMOSTAT
INDOOR UNIT
OUTDOOR UNIT
LOW VOLTAGE TERMINAL BLOCK
IN AIR HANDLER WITH ELECTRIC HEAT
DEFROST
CONTROL
FIELD
INSTALLED
JUMPER
DEHUMIDIFICATION CONTROL CONNECTION
(Humidistat* Jumper must be removed)
GND.
SCREW
CONTACTOR
T2
T1
L2
L1
M
R
L or X
Y
O
W
G
T
2
E
2
R
R
Y
Y
O
O
W2
W
C
C
X/L
G
W1
BK
GND.
LUG
CIRCUIT
BREAKER***
POWER WIRING
24V CONTROL WIRING
(NEC CLASS 2)
JUMPER TERMINALS E AND W TO HEAT
ON FIRST STAGE DURING EMERGENCY HEAT.
TERMINAL NOT USED ON ALL THERMOSTATS.
POWER WIRING
208/230-1-60
230-1-50
CHECK THE LOW VOLTAGE TERMINAL BLOCK ON THE INDOOR UNIT FOR THE ACTUAL ARRANGEMENT OF THE TERMINALS.
CONNECT POWER WIRING TO TERMINAL BLOCK 3TB ON UNITS WITHOUT ELECTRIC HEAT OR CIRCUIT BREAKER.
B or C
ALL FIELD WIRING TO BE IN ACCORDANCE WITH ELECTRIC CODE (NEC) AND/OR LOCAL CODES
RED
BLK
YEL
ORG
WHT
PUR
BRN
1
2
3
4
1
3,4
W1/66
An attempt to start the compressor without at least 8 hours of
crankcase heat will damage the compressor.
