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Prestige IAQ Thermostat Kit w/ RedLINK Internet Gateway, YTHX9421R5127WW

SKU:
YTHX9421R5127WW
Rating:
(11)
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Prestige IAQ Thermostat Kit w/ RedLINK Internet Gateway, YTHX9421R5127WW
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YTHX9421R5127WW has been discontinued
Discontinued June 3, 2026
This product was discontinued by the manufacturer.

Product Highlights

Product Highlight: Programmability
7 Day, Programmable
Product Highlight: Voltage
Low voltage, 24V
Product Highlight: Stages
4 Heat/2 Cool Heat Pump, 3 Heat/2 Cool
Product Highlight: Mount
Horizontal
Product Highlight: Power Method
Hardwired
Product Highlight: Temperature Range (F)
50°F - 99°F (Cooling), 40°F - 90°F (Heating)

Description

Includes:
  • White/white Prestige IAQ thermostat
  • RedLINK Internet Gateway (RIG)
  • Equipment Interface Module (EIM)
  • Supply & Return Sensors
Overview:
The Prestige IAQ thermostat is a 2 wire high definition color touch screen thermostat, 7 day programmable and selectable for residential or light commercial use. Controls up to 4-stages of heat and 2-stages of cool in a heat pump system and up to 3-stages of heat and 2-stages of cool in a conventional system. Three sets of Universal IAQ contacts to control humidification, dehumidification, and ventilation. Four sensor inputs for wired sensors or dry contact devices. Works with the Equipment Interface Module and RedLINK accessories including the RedLINK Internet Gateway, Portable Comfort Control, Wireless Outdoor Sensor and Wireless Indoor Sensor.

Features:
  • Control heating, cooling and IAQ equipment with only 2 wires at the thermostat. Heating, cooling and IAQ equipment wires to the Equipment Interface Module.
  • Smart Schedule - programs in seconds for any lifestyle
  • Patented interview based programming and installer setup.
  • RedLINK wireless communication
  • Increase profit per job by including RedLINK accessories that provide comfort and convenience. RedLINK accessories include the RedLINK Internet Gateway, Portable Comfort Control (PCC), Wireless Outdoor Sensor, Wireless Indoor Sensor, Wireless Entry/Exit Remote, Wireless Vent and Filter Boost Remote, TrueSTEAM humidifier with Wireless Adapter and TrueZONE zoning panel with Wireless Adapter.
  • Selectable for residential and light commercial applications. Meets commercial code and is title 24 compliant.
  • Light commercial - commercial language (occupied and unoccupied), schedule holidays and custom events, remote setback, economizer and time of day.
  • Delta T Alerts and Diagnostics informs customers when their system is not performing as expected with instructions to contact the dealer. Provides a sense of security and greater comfort while generating repeat business.
  • All Prestige® IAQ kits come standard with a return and discharge air temperature sensor to measure Delta T.
  • Alerts and User Interactions Log - Keeps a searchable history of alerts and setting changes to the thermostat to determine if there is a system malfunction or if the issue was caused by user error. Saves time in troubleshooting and points the technician in the right direction.
  • Performance Logs - Keeps a history of heating and cooling performance. The performance log includes Minimum and Maximum Delta T, Minimum and Maximum Discharge Temperature, Minimum and Maximum Return Temperature, Minimum and Maximum Indoor Temperature/Humidity, Minimum and Maximum Outdoor Temperature/Humidity and Run Time. Quickly determine if the system is performing as expected and reduces service time on the job.
  • Customizable Service Reminders allow dealers to remind their customers when its time to call for service, when their warranty is expiring and to provide customized alerts.
  • USB port for transferring Installer Setup, Customizable Reminders, Custom Events and Holidays to multiple thermostats.
  • USB port for adding the dealer's full color business logo on the screen.
  • 3 assignable outputs to control humidification, dehumidification, ventilation and a stage of heating or cooling.
  • 4 assignable inputs on the Equipment Interface Module can be used with wired outdoor, indoor or discharge sensors, occupancy sensor for remote setback and dry contact devices to trip pre-packaged or custom alerts such as a full drain pan or water leak.
  • Extend wireless range of the Equipment Interface Module by connecting a THM4000R1000 Wireless Adapter to the ABCD terminals.
  • Tri-lingual - English, French and Spanish display options.
  • Precise temperature control (+/- 1° F) for reliable and consistent temperature.
  • Multiple staging options to provide comfort or energy savings

Specs

Application:

Heat Pump

Multi-Stage (Heat/Cool)

Stages:

4 Heat/2 Cool Heat Pump

3 Heat/2 Cool

Programmability:

7 Day

Programmable

User Interface:

Touchscreen

Mount:

Horizontal

Options:

Wireless

Fan Control

Auto Changeover

Power Method:

Hardwired

Changeover:

Auto

Manual

Temperature Range (F):

50°F - 99°F (Cooling)

40°F - 90°F (Heating)

Max Temp Differential:

1°F

Operating Humidity:

5 to 90% RH, non-condensing

Voltage:

Low voltage

24V

Color:

Premier White

Height:

4-23/25"

Width:

6-2/5"

Depth:

1-19/46"

Humidity Control:

Yes

Wireless:

Yes

Warranty:

5 Year

Wi-Fi:

Yes

Contact

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Question? Call or text 888-757-4774
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You May Also Need

Prestige IAQ Kit w/ RedLINK, EIM & 4 Sensors, YTHX9421R7001WW
SKU: YTHX9421R7001WW
Honeywell Home

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Product Reviews

4.82 out of 11 reviews
100% would recommend this product
4.82
out of 11 Reviews
100% would recommend this product
WRITE A REVIEW
5 star
82%
4 star
18%
3 star
0%
2 star
0%
1 star
0%
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Showing 1-10 of 11 reviews

Yes

Good
Na
Na
6 years ago
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I would used this product again

Refurbishing a system in 200 year old house and could not run wires for thermostats . So used these along with other HONEYWELL components.
Ed
New Mexico
7 years ago
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yes

This thermostat works great for dual fuel heat pumps. Don't have to worry about running more wires to thermostat capable of 3 stages of heat.
Tim
MA
7 years ago
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Complete package

Great stat. Easy setup. Many options for monitoring system efficiency. App is also easy to use.
Silverhound79
Shippensburg,pa
7 years ago
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Flexible options

Balance 4 zones between two floor that face north and south
JMO
NY
7 years ago
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Great way to UpDate older furnaces to WiFi and control Humid

Great way to UpDate older furnaces to WiFi and control humidity with outdoor reset.
Jack
Richfield Wi
8 years ago
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awesome climate control

love every thing about it except one major issue. the connected app portion of the iaq system is extremely lacking. i would like to be able to monitor temps in different location, with out using them tied to a stat. this isnt possible with iaq system. for instance remote temp sensors cant be added a viewed online, for ref temperatures. they are not easily access able from stat either. you have to go into installer settings to be able to display the temps. this was a major disappointment. In defense of the iaq system, im using it for a custom cooling solution, for home or light commercial, im sure you will be more than happy.
belwarpxl
usa tn
9 years ago
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I've installed many of these

This system requires knowledge of wiring and HVAC equipment to install. Once it is installed, it is very reliable. As a professional, I prefer the security of this control for my customers.
Anonymous
Cincinnati
9 years ago
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My customers love this stat!

It's very user friendly and every one I have installed has had great feedback from my customers. App is easy to use and works great. I will keep selling these with all my installs.
Jeremy
Md
9 years ago
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Great thermostat

Had tried 3 - TH8321R which all had problems with indoor humidity reading dropping 25% during a setback and returning to normal during recovery. Local Honeywell Rep. advised that they just became aware of the problem and that as far as they knew the Prestige YTHX9421R did not have the same software problem. Ordered and installed the Prestige and have had no problems. It is great to be able to check or change thermostat settings while out of town using the Redlink gateway. Also alerts can be set to notify me of problems with the heating or cooling system.
Retired HVAC tech.
Hoffman Estates, IL
9 years ago
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