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Honeywell C7735A1000/U gray return air sensor thermostat

Honeywell

Honeywell C7735A1000/U Return Air Sensor thermostat

SKU CH-5YFE-4NRY9

A return-duct sensor that takes over heating at 62° F and cooling at 82° F when the wireless thermostat loses power

  • TypeThermostat Accessories
  • ColorGray
  • Maintains safe temperatures during power loss with THM5320R1000 Equipment Interface Module
  • Controls heating at 62°F and cooling at 82°F for backup protection
  • Mounts on return duct for non-zoned RedLINK wireless system backup
  • Installs in minutes with included mounting hardware
  • Provides homeowner peace of mind through automatic backup temperature control

Return Air Sensor for Backup Control

The Honeywell C7735A1000/U is a return air sensor designed for non-zoned RedLINK wireless systems. It mounts on the return duct to provide backup temperature monitoring. This accessory is intended for homeowners and HVAC installers who want a failsafe if the wireless thermostat loses power.

Works with THM5320R1000 Equipment Interface Module

When paired with the THM5320R1000 module the sensor takes control of the equipment during a power loss at the thermostat. It activates the blower fan and regulates heating at 62° F and cooling at 82° F. Mounting hardware is included for a quick installation.

Check system compatibility before ordering

Verify that your existing setup uses a compatible RedLINK enabled wireless thermostat and the THM5320R1000 Equipment Interface Module. This sensor will not function as a standalone thermostat or with zoned systems. Ensure you have access to the return duct for mounting.

Highlights

  • Maintains safe temperatures during power loss with THM5320R1000 Equipment Interface Module
  • Controls heating at 62°F and cooling at 82°F for backup protection
  • Mounts on return duct for non-zoned RedLINK wireless system backup
  • Installs in minutes with included mounting hardware
  • Provides homeowner peace of mind through automatic backup temperature control

Specifications

BrandHoneywell
TypeThermostat Accessories
ColorGray

Questions about this item

Does the return air sensor require any periodic calibration or component replacement to keep the backup control accurate?

The sensor is a passive duct-mounted device with no moving parts or batteries, so no scheduled calibration or replacement is needed under normal operation.

What temperature limit does the backup control enforce first during a prolonged power loss at the wireless thermostat?

Heating is held at 62° F and cooling at 82° F; whichever set-point is reached first will activate the equipment to maintain that limit.

How much heat does the sensor itself generate when it is powered continuously on the return duct?

The unit draws only milliamps from the Equipment Interface Module, so its self-heating is negligible and does not affect the return-air reading.

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