Resideo - Honeywell Home THM5421R1021 Thermostat Equipment Interface Module

Thermostat Equipment Interface Module from Resideo - Honeywell Home, model THM5421R1021, is a versatile 2-wire IAQ thermostat interface designed for reliable, hardwired control. This vertical-mount, gray module supports up to 4-Heat/2-Cool heat pump or up to 3-Heat/2-Cool conventional configurations and is compatible with THX9421R5021 and Prestige/VisionPRO systems. Its compact size (4-13/16 W x 1-5/8 D x 9-5/16 H) ensures a clean fit in standard panels.

Key specs and compatibility:

• Voltage: 18 to 30 VAC (50/60 Hz)
• Current: 1 A (Heat/Cool), 0.5 A (Fan)
• Power: Hardwired
• Mounting/Finish: Vertical, Gray
• Staging: Up to 4-Heat/2-Cool heat pump or up to 3-Heat/2-Cool conventional
• Environment: Humidity 5–95% RH non-condensing; Temperature -40 to 165°F
• Terminals: R, RC, RH, C, W-O/B, W2-AUX1, W3-AUX2, Y, Y2, G, A-L/A, U1, U2, U3, S1, S2, S3, S4, A, B, C, D
• Applications: Gas, Oil, Electric, Heat Pump, Forced Warm Air, Hot Water, Steam or Gravity