THX9321/9421 P restige® IAQ and RF EIM
21 69-2490 —03
Humidification
Thethermostatcanbesettocontrolhumidificationinallmodes (Heat,Off,Cool
[ISU8060]).Adischargeairsensorisrequiredtohumidifyinthe coolmode.If
bothhumidificationanddehumidificationaresetuptobecontrolledinthe same
mode(Heat,Off,Cool),thethermostatmaintainsa15%deadbandbetween
humidificationanddehumidificationsetpoints.Thethermostatautomatically
switchesbetweenhumidificationanddehumidificationtomaintainthedesired
humidity level.
HumidificationControlOptions:(ISU8070)
• HumidifyOnlyWhenHeatisOn
• HumidifyOnlyWhenFanisOn
• HumidifyonDemand:ThermostatControlsFan
• HumidifyonDemand:HumidifierControlsFan
Residential dehumidification
DehumidificationEquipmentOptions:(ISU9000)
• A/CwithLowSpeedFan
• A/CwithHighSpeedFan
• WholeHouseDehumidifier
WhensetforA/C with Low Speed Fan or A/C with High Speed Fan,anovercool-
inglimitcanbesetfrom0°to3°F(ISU 9070).Thethermostatusesthecooling
systemtoreducehumiditybyloweringthetemperatureupto3°F belowthe
currentcoolsetpointuntilthethedesiredhumiditylevelisreached.If setfor
A/C with Low Speed Fan,configureU1,U2orU3asnormallyopenornormally
closed(ISU9050)andwiretheterminaltotheLowSpeed Fanterminalonthe
equipment.Duringacallfordehumidification,thethermostatopensor closesthe
universalrelay(U1,���U2orU3)tolowerthefanspeed.
Note:Thethermostatwillnotlowerthefanspeedwhen thesecondstageof
coolingison.
TheWhole House Dehumidifieroptionrequiresadedicatedunitfordehumidifica-
tion.Thethermostatcanbesettocontroldehumidificationinall modes(Heat,
Off,Cool[ISU9120]).
Ifbothhumidificationanddehumidificationaresettobecontrolledinthe same
mode(Heat,Off,Cool),thethermostatmaintainsa15%deadbandbetween
humidificationanddehumidificationsetpoints.Thethermostatautomatically
switchesbetweenhumidificationanddehumidificationtomaintainthedesired
humidity level.
To see all humidification options, press Menu > Installer Options > View/Edit Current Setup > Humidification.
To see all dehumidification options, press MENU > INSTALLER OPTIONS > VIEW/EDIT CURRENT SETUP >
DEHUMIDIFICATION.
69-2490_B.indd 21 7/13/2011 1:42:01 PM