Honeywell THM5421 Catalog Page

Programmable Thermostats

THM5421 Equipment Interface Module for Prestige® IAQ and
VisionPRO® 8000 with RedLINK™

Equipment Interface Module controls up to 4-stages of heat and 2­stages 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.

Application: Gas, oil, electric, heat pump, forced warm air, hot water,

steam or gravity

Dimensions, Approximate: 9 5/16 in. High, 4 13/16 in. Wide, 1 5/8 in.

Deep (237.4 mm High, 122.5 mm Wide, 40.6 mm Deep)

Color: Gray
Electrical Connections: Screw terminals
Electrical Ratings: 18 to 30 Vac
Operating Humidity Range (% RH): 5 to 95% RH, non-condensing
Operating Temperature Range: -40 F to 165 F (-40 C to 73.9 C)
Currents (Cooling): 1.0 A running
Currents (Heating): 1.0 A running
Currents (Fan): 0.5A running
Frequency: 50 Hz; 60 Hz
Power Method: Hardwired
Mounting: Ver tica l

Product Number Terminal Designations Stages Includes Used with

THM5421R1021/U R, RC, RH, C, W-O/B, W2-AUX1, W3-

YTHM5421R1010/U R, 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

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

Up to 4 Heat / 2 Cool Heat Pump or
Up to 3 Heat / 2 Cool Conventional

Up to 4 Heat / 2 Cool Heat Pump or
Up to 3 Heat / 2 Cool Conventional

— Prestige® IAQ 2-Wire

THM5421R1021 and
2 Duct Sensors

Thermostat and VisionPRO®
Thermostat with RedLINK™

Prestige® IAQ 2-Wire
Thermostat and VisionPRO®
Thermostat with RedLINK™

Commercial

Components

70-6910 505