Honeywell TH8321 - WIRING IAQ EQUIPMENT AND STAGES TO U1 TERMINALS; Wiring IAQ Devices to U1 Terminals; Wiring Heat;Cool Stages to U1 Terminals

VISIONPRO® 8000 SMART THERMOSTAT
33-00096—04 86
Wiring IAQ Equipment or a Heat/Cool Stage to the U1 Terminals
To Thermostat
“U” terminals can be used for humidification, dehumidification, ventilation or a stage of heating/cooling.
Fig. 225. Wiring a powered humidifier, dehumidifier, or
ventilator.
Fig. 226. Dehumidification with low speed fan using a
variable speed blower.
1Wire the thermostat U1 contact to the low speed fan for
dehumidification control at the equipment. The thermo-
stat relay can be set to normally open or normally closed
in the thermostat installer setup.
Fig. 227. Wiring a non-powered humidifier, dehumidifier,
or ventilator.
Fig. 228. Wiring a heat or cool stage to U1.
1U1 terminals are normally open dry contacts when set up
for a stage of heating or cooling.
2You must install a field jumper if the stage of heating or
cooling is powered by system transformer. Do NOT install
a field jumper if the stage of heating has its own trans-
former.
Normally open, dry contacts
Normally closed, dry contacts
C
K
R
C
R
U1
U1
120
VAC
24
VAC
C
R
SYSTEM
TRANSFORMER
120
VAC
24
VAC
HUM, DEHUM OR
VENT
TRANSFORMER
THERMOSTAT
POWERED
HUMIDIFIER,
DEHUMIDIFIER
OR VENTILATOR
1
C
K
R
C
R
U1
U1
120
VAC
24
VAC
C
R
SYSTEM
TRANSFORMER
THERMOSTAT
DEHUMIDIFICATION
WITH LOW SPEED FAN
FIELD INSTALL JUMPER
BETWEEN R AND U1
OR
C
K
R
C
R
U1
U1
120
VAC
24
VAC
C
R
SYSTEM
TRANSFORMER
THERMOSTAT
NON-POWERED
HUMIDIFIER,
DEHUMIDIFIER
OR VENTILATOR
FIELD INSTALL JUMPER
BETWEEN R AND U1
2
C
K
R
C
R
U1
U1
120
VAC
24
VAC
C
R
TRANSFORMER
THERMOSTAT
HEAT STAGE 3, COOL
STAGE 3, BACKUP HEAT
STAGE 2 FOR HEAT
PUMPS, OR GEOTHERMAL
RADIANT HEAT
1