Honeywell Vision PRO IAQ Touchscreen Thermostat, Programmable, 7-day, 4H/2C

VisionPRO IAQ Programmable Thermostat


Brand: Honeywell

Mfr Part#: TH9421C1004

UPC#: 085267264846

Availability: Out Of Stock
Usually ships: Upon availability
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$183.67 / each
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Honeywell TH9421C1004 Vision PRO IAQ Thermostat features 7 day programming and is designed for Up to 3 Heat/2 Cool Conventional Systems and Up to 4 Heat/2 Cool Heat Pumps.

Honeywell Vision PRO IAQ Thermostat provides electronic control of 24 Vac heating and cooling systems in addition to humidification, dehumidification and ventilation all with just 3 wires to the thermostat.. Honeywell TH9421C1004 offers you top-of-the-line features like Touchscreen interaction, a real-time clock, and a large, easy-to-read backlit display.



  • Advanced dual-fuel control;
  • Three wires to the living space allows for easy equipment upgrade without having to run additional thermostat wire;
  • Thermostat connects with Equipment Interface Module or EnviraZONE panel to control temperature, humidification, dehumidification and ventilation from a single point in the home;
  • Automatically raises humidity levels throughout all rooms in the home, moisturizing air to prevent symptoms of dryness and to protect hardwood flooring and woodwork;
  • Removes air pollutants by exchanging the stale air in a house with fresh, filtered air better than having an open window;


Technical Specifications of Honeywell TH9421C1004:

  • Programmability: 7 Day Multiple Day Programming or Non-Programmable;
  • Changeover: Auto/Manual Selectable;
  • Color: Premier White;
  • Switch Positions (System): HEAT-OFF-COOL-AUTO-EM.HEAT;
  • Switch Positions (Fan): AUTO-ON-CIRC;
  • Power Method: Communicating;
  • Terminal Designations: 1, 2, 3;
  • Dimensions: 4 9/16" high x 6" wide x 1 1/4" deep;
  • Mounting: Horizontal;
  • Electrical Ratings: THM5421 is rated 20 to 30 Vac;
  • Setting Temperature Range: Heat: 40F to 90F; Cool 60F to 99F;
  • Differential Temperature: +/- 1F;
  • Stages: Up to 4 Heat/2 Cool Heat Pump;
  • Stages: Up to 3 Heat/2 Cool Conventional;
  • Outdoor Sensor: Yes, optional;
  • Discharge Sensor: Yes, optional;
  • Remote Sensor: Yes, optional;
  • Sensor Element: Thermistor;
  • Operating Humidity Range (% RH:) 5 to 90% RH, non-condensing;
  • Includes: Thermostat only;
  • Comments: Includes Humidification Control with or without Frost Protection, Dehumidification using Whole House Dehumidifier or Air Conditioning with High or Low speed fan, Advanced Patented Ventilation Control and Advanced Dual Fuel Heat Pump Control.;
  • Used With: THM5421C1008 Equipment Interface Module;
  • Display Size: 10 sq inch;
  • Humidification Setting Range: 10 to 60% RH.;
  • Dehumidification Setting Range: 40 to 80% RH.;
  • Voltage: 20 to 30 Vac;
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Error 89?
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This means that the thermostat cannot establish a connection with the equipment. This could be caused by a number of issues, such as a faulty/loose wire or malfunctioning equipment.
Answered on 9/4/2012 by PexUniverse Customer Service
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