The Honeywell Home DT4R Grey Wireless Room Thermostat Spare (DTS42GRFST21) provides convenient room temperature control for compatible domestic heating systems in homes and apartments. Featuring a slim, modern grey design, a large LED segment display and easy-to-use backlit touch buttons, it combines a contemporary appearance with straightforward temperature adjustment.
This DT4R model is supplied as a spare wireless thermostat head only and does not include a wireless receiver. It is designed for use with compatible Honeywell Home heating control systems, including evohome and the HCC100 Underfloor Multi-Zone Controller. Its Ramses II and Ramses III RF protocol supports compatibility with suitable existing Honeywell Home wireless products.
Honeywell Home DT4R Range Wireless RF Grey Finish Spare Thermostat Only
Important – No Receiver Included
This listing is for the DT4R grey thermostat head only. A compatible Honeywell Home wireless receiver or control system is required and must be purchased separately if not already installed.
Key Features & Benefits
1. Grey DT4R Spare Wireless Thermostat
A replacement thermostat head for compatible Honeywell Home wireless heating systems, suitable for replacing an existing unit or extending an appropriate installation.
2. Ramses II and Ramses III RF Compatibility
Uses Honeywell Home's Ramses II and Ramses III RF protocols, providing backwards and forwards compatibility with suitable compatible wireless products.
3. Clear, Energy-Efficient LED Display
The large LED-based segment display makes temperature information easy to read and automatically turns off when not in use to help conserve energy.
4. Backlit Touch Controls
Backlit, captive touch buttons provide convenient temperature adjustment and straightforward everyday operation.
5. Built-In Eco Mode
The built-in Eco mode reduces room temperature for a selected period, helping manage heating use and reduce energy consumption.
6. Supports Modern Heating Applications
Designed for compatible heating systems, including conventional and combi boilers, heat pumps, zoning, underfloor heating and cooling devices, and zone valve applications.
Compatibility and Applications
The Honeywell Home DT4R Grey Spare Thermostat is designed to integrate with suitable existing Honeywell Home wireless heating controls.
- Compatible Honeywell Home evohome systems.
- HCC100 Underfloor Multi-Zone Controller.
- Compatible Honeywell Home RF products using Ramses II/III protocols.
- Suitable conventional and combi boiler applications.
- Compatible heat pump installations.
- Heating zoning and zone valve applications.
- Compatible underfloor heating and cooling devices.
Important: This thermostat is not suitable for direct control of 240V electric heating circuits. Check the compatibility of your existing receiver and heating appliance before purchasing.
Technical Specifications
| Manufacturer |
Honeywell Home by Resideo |
| Product Range |
DT4 |
| Model |
DT4R Grey Spare Thermostat |
| Manufacturer Part Number |
DTS42GRFST21 |
| SKU |
46414 |
| EAN / GTIN |
5059085002688 |
| Product Type |
Spare Wireless Room Thermostat |
| Colour |
Grey |
| Control Type |
Wireless RF |
| RF Protocol |
Ramses II and Ramses III |
| Display |
LED Segment Display |
| Eco Mode |
Yes – timed temperature reduction |
| Compatible Systems |
Compatible evohome and HCC100 systems |
| Receiver Included |
No – thermostat head only |
| Weight |
Not specified |
| Warranty |
2 years, subject to manufacturer's terms and conditions |
Frequently Asked Questions
Does the Honeywell Home DT4R Grey thermostat include a wireless receiver?
No. The DTS42GRFST21 is a spare thermostat head only. A compatible wireless receiver is not included and must already be available in the heating system.
Can this thermostat work with an existing heating system?
Yes, it is designed to work with compatible existing Honeywell Home wireless systems, including suitable evohome and HCC100 configurations. Check the receiver protocol and model before ordering.
What is the difference between wireless RF and Wi-Fi heating controls?
Wireless RF controls communicate with compatible heating receivers using a dedicated radio-frequency protocol. Wi-Fi controls use a wireless network for connected features. The supplied DT4R information specifies Ramses II/III RF communication and does not specify built-in Wi-Fi connectivity.
Does installing this thermostat require a professional?
Installation and pairing should follow the manufacturer's instructions. If receiver wiring, boiler connections or changes to the heating system are required, use a suitably qualified heating controls professional.
Can this thermostat control 240V electric heating?
No. The supplied product information states that it is not suitable for direct control of 240V electric heating circuits.
Order Honeywell Home DT4R Grey Spare Thermostat from GetPlumb
Choose the Honeywell Home DT4R Grey Wireless Room Thermostat Spare DTS42GRFST21 for a compatible existing wireless heating control system. Its modern grey finish, LED display and convenient touch controls make it a practical replacement thermostat for suitable installations.
Order Now from GetPlumb for your heating control requirements.
