Honeywell Home YTHM5421R1010/U Prestige® 2-Wire IAQ Equipment Interface Module Kit With Two Duct Sensors

The YTHM5421R1010 is a Prestige 2-wire IAQ equipment interface module from Resideo (Honeywell Home), supplied as a kit with two duct sensors.

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.

This version includes two duct sensors, which are what the module needs to see supply and return conditions.

Goes with: THX9421R5021WW, THM5421R1021.

• Brand: Resideo (Honeywell Home)
• Manufacturer Part #: YTHM5421R1010/U
• Type: Prestige 2-wire IAQ equipment interface module kit
• Supply voltage: 18 to 30 Vac
• Connections: Screw terminals
• Operating temperature: -40 °F to 165 °F
• Category: RedLINK Accessories

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