Your browser is not supported. For the best experience, you should upgrade to a modern browser with improved speed and security.

Honeywell THM5421R1021 - Prestige® 2-Wire IAQ Equipment Interface Module

Item: THM5421R1021
MFR: THM5421R1021/U
Checking price...
Decrease quantity
Increase quantity

Your Order Templates
Save products for later, or create lists to quickly re-buy items for routine jobs.

Add to Order Template

Inventory At Nearby Branches



Equipment Interface Module 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.


NameHoneywell THM5421R1021 - Prestige® 2-Wire IAQ Equipment Interface Module
Gemaire Item NumberTHM5421R1021
Manufacturer Product NumberTHM5421R1021/U
SKU - PIM Number1374780270684
ERP Number331911
Unit of MeasureEACH
Weight1.0 Pound (lb.)
Length9.8 Inches (in)
Width2.2 Inches (in)
Height5.8 Inches (in)
Hazardous MaterialNo
EPA Cert RequiredNo
Country of OriginMEX
Voltage18-30 VAC
Electrical ConnectionScrew terminals
Electrical Rating18 to 30 VAC
Power MethodHardwired
IncludesTHM5421R1021 Equipment Interface Module
ApplicationGas, oil, electric, heat pump, forced warm air, hot water, steam or gravity
Operating Humidity5 to 95% RH, non-condensing
Operating Temperature Range-40°F to 165°F (-40°C to 73.8°C)
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
Used WithAll THX9421R5021 Prestige 2-Wire IAQ Thermostats and all versions of Prestige IAQ Thermostats and the VisionPRO Thermostats with RedLINK™ technology.
Warranty Offered5 Year
Stages Cool2
Stages Heat3
GEM - Case Quantity