Honeywell
Honeywell THM5421R1021 Equipment Interface Module
Order by 2 PM ET on business days — same-day shipping on in-stock items
🔒 Guaranteed Safe & Secure Checkout
In-stock orders placed by 2 PM ET on business days ship the same day. Free shipping on every continental US order. Estimated delivery 3–5 business days via USPS, UPS, or FedEx (carrier selected at our discretion).
- Same-day shipping on in-stock orders placed by 2 PM ET (business days)
- Estimated delivery 3–5 business days, continental US only
- Tracking emailed within 24 hours
- 30-Day Returns
Product Description
Honeywell THM5421R1021 — Equipment Interface Module
Overview
The Honeywell THM5421R1021 Equipment Interface Module is a genuine OEM component engineered for reliable performance in residential and commercial heating and cooling systems. The THM5421R1021 is built to Honeywell's demanding quality standards, ensuring dependable operation over its service life. The THM5421R1021 is a trusted choice for HVAC technicians requiring accurate, direct-fit replacement parts.
Key Features
- Controls high-stage equipment and IAQ accessories using only two wires at the thermostat
- Compatible with Prestige IAQ and VisionPRO 8000 with RedLINK thermostats
- Three sets of Universal IAQ contacts control humidification, dehumidification, and ventilation
- Four sensor inputs accommodate wired sensors or dry contact devices
- Wide operating temperature range suitable for installation in unconditioned spaces
Technical Specifications
| Specification | Value |
|---|---|
| Type | Equipment Interface Module (EIM) |
| Stages | Up to 4 Heat/2 Cool Heat Pump, 3 Heat/2 Cool Conventional |
| Voltage | 18 to 30 VAC, 50/60 Hz |
| Humidity Rating | 5 to 95% RH |
| Operating Temperature | -40 to 165 deg F |
| Dimensions | 9-5/16 in H x 4-13/16 in W x 1-5/8 in D |
| IAQ Contacts | 3 Sets of Universal IAQ Contacts |
| Sensor Inputs | 4 Inputs for Wired Sensors or Dry Contact Devices |
Applications
This component is commonly used in multi-stage residential heating and cooling systems using RedLINK-enabled thermostats.
Frequently Asked Questions
What is the Honeywell THM5421R1021 used for?
The Honeywell THM5421R1021 is used as a equipment interface module in residential and commercial heating and cooling systems.
How do I confirm the THM5421R1021 is the right fit for my system?
Always verify the part number, voltage, and physical dimensions against your equipment nameplate or original part before ordering.
Where can I buy the Honeywell THM5421R1021?
You can buy the genuine Honeywell THM5421R1021 directly from coolingpartssupply.com with Free UPS Ground Shipping on all orders.
What is the warranty on the THM5421R1021?
The THM5421R1021 is backed by a 1-year warranty. For warranty support, contact support@coolingpartssupply.com.
Specifications
| Brand | Honeywell |
|---|---|
| Product Type | Thermostat Accessories |
| SKU | THM5421R1021 |
| Condition | New |