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Honeywell Home DT4R Wireless Thermostat & Receiver | YT42WRFT20
Regular price
£69.00
Inc. VAT
£57.50
Exc. VAT
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The Honeywell Home DT4R (YT42WRFT20) is a wireless, battery-powered room thermostat supplied as a complete pack with a mains-powered relay receiver. Fix the receiver beside the boiler, heat pump or zone valve, place the thermostat wherever the room actually needs it, and the two communicate over encrypted 868 MHz radio with no thermostat cable run back to the heat source.
Control is on/off with fuzzy logic, switching 24-230 V appliances such as gas boilers, combi boilers and heat pumps, as well as 2-port zone valves. A large LED segment display with adjustable brightness, coloured status icons and a wake-up button keeps operation simple, while a timed Eco/boost offset of up to ±3 °C and built-in frost protection at 5 °C cover everyday comfort and pipework protection.
Because the DT4R is backwards compatible with existing Honeywell Home RF products, including the BDR91A relay box, it also suits upgrades and replacements. The installer menu lets you tune cycle rate, minimum on/off times, set-point limits and heat/cool changeover to the appliance, and the range carries a 5-year manufacturer warranty.
868 MHz
Encrypted RF band
30 m
Typical RF range indoors
5-35°C
Set-point range
24-230 V
On/off appliance switching
1.5 yrs
Battery life (2 × AA)
5 yrs
Manufacturer warranty
Mains wiring and installation
The receiver is powered from 230 V AC mains and switches mains-rated appliance circuits. Isolate the supply before wiring. Work on boiler or heat pump controls must be carried out by a competent person (Gas Safe registered where gas appliances are involved) in line with BS 7671 and the appliance manufacturer's instructions.
evohome and HCC100 compatibility - please check before ordering
The manufacturer's comparison table lists the BDR91A relay box as the Honeywell Home product compatible with this YT42WRFT20 pack, and lists evohome, HCC100, HCE80, HCC80 and ST9000 against the separate DTS42WRFST20 spare thermostat. The datasheet also describes the DT4 range as designed to work with zoning applications such as evohome/HCC100. If you plan to integrate this thermostat into an evohome or HCC100 system, contact our team to confirm the right part first.
On/off control only - not for direct electric heating
This is the on/off version. It does not support OpenTherm® modulation (see the YT43MRF series in the range table below) and the manufacturer states it is not for electric heating at 240 V. The receiver is a control switch rated 5 A resistive / 3 A inductive, not a heater-load switch. It also has no built-in time schedule, so add separate time control where your system requires it.
New installation or upgrade
In a new installation the thermostat and receiver supplied in the pack work as a pair. When upgrading an existing system, the thermostat can be bound to a compatible Honeywell Home RF receiver such as the BDR91A, so the new receiver may not be needed. Binding is set in the installer menu, and the receiver's reset button deletes an existing binding.
Key features
Complete wireless pack
Thermostat and 230 V relay receiver in one box. Only the receiver is wired, to a terminal block accepting up to 2.5 mm² with cable access from the bottom and cable clamps.
Clear LED display
Large LED segment display with adjustable brightness, coloured status icons (heat, cool, wireless signal, eco, off, low battery, warning) and a wake-up button. The screen switches off when not in use.
Fuzzy logic control
Fuzzy logic with a selectable cycle rate and installer-set minimum on and off times for a stable room temperature and sensible appliance cycling.
Eco and boost offset
A timed Eco Offset of -3 to +3 °C in 0.5 °C steps, held for 1-24 hours. Negative values reduce demand for savings; positive values give a temporary boost.
Frost protection and limits
The 'Off' position keeps a 5 °C frost-protection minimum. Installers can raise the lower and lower the upper set-point limits to 21 °C, ideal for tenanted or vulnerable-occupant properties.
Heat, cool or both
User menu offers heating, cooling or heating and cooling modes with changeover set by the installer, suited to heat pumps and cooling-capable appliances that accept an on/off demand.
Built for installers
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Flip-up wiring platform for easy wiring
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Table-stand or wall-mounted thermostat options for new and replacement jobs
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Receiver mounts directly on the wall or on a wall box
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Receiver has a status LED, manual override button and reset button
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Failsafe: if the sensor or radio link is lost, the receiver cycles the demand 20% on / 80% off
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Installer menu: LED brightness, cycle rate, heat/cool changeover, set-point limits, minimum on/off time, Eco Offset temperature, binding and factory reset
What's in the box
Pack contents
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Honeywell Home DT4R white wireless room thermostat
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Wireless relay receiver (230 V AC mains powered)
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2 × AA alkaline batteries for the thermostat
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Wiring plate and mounting fittings
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Installation literature in 14 languages, including English
System compatibility
Technical specifications
DT4R wireless range at a glance
Frequently asked questions
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
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