Your browser is not supported. For the best experience, you should upgrade to a modern browser with improved speed and security.
2017 Fall Training Schedule is Available. “Sign Up Today!” by clicking here.

Prestige® 2-Wire IAQ Equipment Interface Module Kit with 2 Duct Sensors

Item: YTHM5421R1010
MFR: YTHM5421R1010/U

Store Inventory

Sign in to see real-time inventory at the stores closest to you.
What’s the price?
Sign in for pricing.
Decrease quantity
Increase quantity

Frequently Bought Together

Best Sellers

About This Product

Product Info


Equipment Interface Module Kit with 2 Duct Sensors. Controls up to 4-stages of heat and 2-stages of cool in a heat pump system and up to 3-stages of heat and 2-stages of cool in a conventional system. Three sets of Universal IAQ contacts to control humidification, dehumidification, and ventilation. Four sensor inputs for wired sensors or dry contact devices. Used with all versions of Prestige IAQ Thermostats and the New RedLINK VisionPRO Thermostats.


Weight5.25 Pounds (lbs)
Width4.8125 Inches (In)
Height9.3125 Inches (In)
Country of OriginMEX
UPC or Barcode085267386524
Hazardous MaterialNo
EPA Cert RequiredNo
Length1.625 Inches (In)
ApplicationGas, oil, electric, heat pump, forced warm air, hot water, steam or gravity
Electrical Rating18 to 30 VAC
For Use WithAll THX9421R5021 Prestige® 2-Wire IAQ Thermostats and all versions of Prestige® IAQ Thermostats and the VisionPRO® Thermostats with RedLINK™ technology.
Humidification5 to 95% RH, non-condensing
IncludesTHM5421R1021 Equipment Interface Module and 2 Duct Sensors
Operating Humidity5 to 95% RH, non-condensing
Operating Temperature Range-40°F to 165°F (-40°C to 73.8°C)
Power MethodHardwired
Stages Cool2
Stages Heat4
Terminal DesignationsR, RC, RH, C, W-O/B, W2-AUX1, W3-AUX2, Y, Y2, G, A-L/A, U1, U1, U2, U2, U3, U3, S1, S1, S2, S2, S3, S3, S4, S4, A, B, C, D
Voltage18-30 VAC
Warranty Offered5 Year

Equipment Part List

Shop Honeywell products