| Supply Voltage | 18 to 30 Vac |
| Frequency | 50 Hz; 60 Hz |
| Electrical Connections | Screw terminals |
| Electrical Ratings | 18 to 30 Vac |
| Operating Temperature | -40 F to 165 F |
| Operating Humidity | 5 to 95% RH, non-condensing |
| Mounting | Vertical |
| Application | Gas, oil, electric, heat pump, forced warm air, hot water, steam or gravity |
| Used With | All THX9421R5021 Prestige® 2-Wire IAQ Thermostats and all versions of Prestige® IAQ Thermostats and the VisionPRO® Thermostats with RedLINK™ technology. |
| Includes | THM5421R1021 Equipment Interface Module |
| Dimensions | 9 5/16 in. High, 4 13/16 in. Wide, 1 5/8 in. Deep |
| Stages | Up to 4 Heat / 2 Cool Heat Pump or Up to 3 Heat / 2 Cool Conventional |
| Power Method | Hardwired |
| Color | Gray |
| Terminal Designations | 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 |
| Cool Current | 1.0 A running |
| Heat Current | 1.0 A running |
| Fan Current | 0.5A running |
Description
The THM5421R1021 is a Prestige 2-wire IAQ equipment interface module from Resideo (Honeywell Home).
RedLINK is the wireless link Resideo uses between a thermostat and the rest of the system. Instead of pulling a wire from the equipment to every sensor and module, the devices are enrolled to the thermostat or to a wireless adapter and talk to it directly — which is what makes a sensor in a room with no thermostat wire, or an outdoor sensor with no conduit to the attic, a realistic job rather than a demolition project.
Enrolment is the step that decides whether it works. Each device has to be added to the system at the thermostat or the adapter; a RedLINK device that has not been enrolled is inert, and one enrolled to the wrong system stays enrolled until it is cleared.
The equipment interface module is what makes the 2-wire installation possible. It lives at the equipment and carries all the terminals — heat, cool, fan, humidification, dehumidification, ventilation — while only two wires run up to the thermostat. On a retrofit that is the whole argument: a Prestige system on the existing pair, with no new cable through finished walls.
IAQ here means the module also drives the indoor air quality equipment — humidifier, dehumidifier, ventilator — rather than leaving each one on its own control fighting the others.
Goes with: THX9421R5021WW.
- Brand: Resideo (Honeywell Home)
- Manufacturer Part #: THM5421R1021/U
- Type: Prestige 2-wire IAQ equipment interface module
- Supply voltage: 18 to 30 Vac
- Connections: Screw terminals
- Operating temperature: -40 °F to 165 °F
- Category: RedLINK Accessories