The Honeywell Home DT4R Black Wireless Room Thermostat (spare unit, model DTS42BRFST22) is a replacement RF thermostat head designed to pair with existing Honeywell Home wireless heating systems. Its slim, modern black finish brings together simple functionality with a large, clear LED segment display and an easy wake-up button, and is backwards compatible with existing evohome and HCC100 receivers via the Ramses II/III RF protocol.
As a spare thermostat only, this unit is intended to replace a faulty DT4R head or expand an existing wireless system, rather than to be fitted as a standalone kit. It works with 24-230V on/off appliances including gas boilers, combi boilers and heat pumps, and supports zoning, underfloor heating and cooling devices, making it a versatile addition to hybrid and greener energy heating setups (note: not compatible with electric heating on 240V circuits).
Black
Colour Finish
Spare Unit
Thermostat Only
2 x AA
Battery Powered
5-35 °C
Set Point Range
30 m
Residential RF Range
2 Years
Manufacturer Warranty
Spare Thermostat Head Only
This listing is for the DT4R thermostat head only - it is designed as a replacement or expansion unit for an existing Honeywell Home evohome or HCC100 wireless system, and does not include a receiver box. Ensure you already have a compatible receiver installed before ordering.
Broad System Compatibility
The DT4R pairs with evohome and HCC100 Underfloor Multi-Zone Controller receivers, and is backwards and forwards compatible with existing Honeywell Home RF products thanks to the Ramses II/III protocol. It supports heat pumps, zoning, underfloor heating and cooling devices, and zone valve applications.
Not for Electric Heating Circuits
The DT4R is compatible with 24-230V on/off heating and cooling appliances such as gas boilers, combi boilers and heat pumps, but is not suitable for direct control of 240V electric heating circuits. Check your system type before ordering.
Slim, Modern Black Design
A slim thermostat profile in black with a large, clear LED segment display suits contemporary interiors while remaining easy to read at a glance.
Auto-Off LED with Wake Button
The auto-off display conserves battery life between uses, with a simple wake-up button to bring the screen back on when needed.
Backlit Touch Controls
Backlit, captive touch buttons make adjusting the temperature straightforward in low light, day or night.
Built-In Eco Mode
A built-in eco-mode applies a timed temperature reduction to help cut energy use without manual intervention.
Ramses II/III RF Protocol
Operates on Honeywell Home's Ramses II/III wireless protocol for reliable communication with compatible evohome and HCC100 receivers, without requiring an internet connection.
Simple Battery-Powered Operation
Runs from 2 x AA batteries, with automatic receiver binding for straightforward setup once paired.
General
Brand
Honeywell Home by Resideo
Model
DT4R Black Spare Thermostat
MPN
DTS42BRFST22
GTIN / EAN
5059085002695
Colour
Black
Product Type
Spare wireless thermostat head (no receiver included)
Performance
Power Supply
2 x AA batteries
Set Point Range
5 °C to 35 °C
Display Range
0 °C to 40 °C
Sensor Type
10k NTC thermistor @ 25 °C
RF Frequency
ISM 868.0 - 868.6 MHz (Ramses II/III)
RF Range
Approx. 30 m (residential)
ErP Contribution Class
Class V (+3%)
Compatibility
Compatible Receivers
evohome, HCC100 Underfloor Multi-Zone Controller, compatible legacy RF systems
Appliance Compatibility
24-230V on/off appliances: gas boilers, combi boilers, heat pumps
Also Supports
Zoning, underfloor heating and cooling devices, zone valve applications
Not Compatible With
Direct 240V electric heating circuits
Physical & Warranty
Dimensions (W x H x D)
101 x 101 x 54 mm
Weight
0.25 kg
Warranty
2 years
Does this come with a receiver box?
No. This is the DT4R thermostat head only, intended as a spare or replacement for an existing Honeywell Home wireless system. You will need a compatible receiver, such as evohome or HCC100, already installed to use it.
What systems is the DT4R Black compatible with?
It works with evohome and HCC100 Underfloor Multi-Zone Controller receivers, and is backwards and forwards compatible with existing Honeywell Home RF wireless heating products via the Ramses II/III protocol.
Can I use this to control electric heating?
No, the DT4R is designed for 24-230V on/off appliances such as boilers and heat pumps, and is not suitable for direct control of 240V electric heating circuits.
How is the thermostat powered?
It runs on 2 x AA batteries, with an auto-off LED display and wake-up button to help conserve battery life between uses.
What is the wireless range of this thermostat?
The DT4R communicates over the 868.0-868.6 MHz ISM band with a typical residential range of around 30 metres, though this can vary depending on walls, floors and other obstructions.
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
Documentation
Do you have a question about this product?
One of our expert advisors will be happy to help you!
