Honeywell Lyric T4, T4R & T4M Programmable Thermostats
Product Specification Sheet
Product Overview
The Honeywell Lyric T4, T4M, and T4R thermostats are designed to provide automatic time and temperature control for heating systems in homes and apartments. The T4 is compatible with 24-230V on/off appliances like gas boilers, combi-boilers, and heat pumps, and also works with zone valve applications (but not electric heating at 240V). The T4M and T4R versions support OpenTherm® appliances.
The T4 and T4M are designed for wired wall installations, while the T4R is a wireless system consisting of a thermostat and a Receiver box. The solution is installer-focused, featuring a Receiver module with flexible mounting options and a terminal platform that simplifies wiring.
The thermostat boasts a large, clear fix-segment display with backlight and a simple programming philosophy, making it easy to install and user-friendly. The T4 product line is ideal for consumers seeking modern design, remote comfort control, and ease of use.
Features
- Minimalistic and modern design to blend seamlessly into any home decor.
- Table stand or wall-mounted options for new and replacement installations.
- Backlight for clear viewing in all lighting conditions.
- Factory-programmed daily, weekly, or 5+2 default heating schedules.
- Schedule options with 4 or 6 independent set-points to suit comfort needs.
- Set-point temperature is always displayed.
- OFF position includes an integral frost protection setting at a minimum of 5 °C to prevent pipes from freezing.
- Alert messages for fault finding assistance.
- Timed override function allows holding a targeted set-point for 1 or 2 hours.
- Away mode reduces temperature for a period of 1 to 99 days.
- Automatic time clock adjustment for Daylight Saving Time (DST).
- Receiver box with clear LED indication and override button.
- On/Off or OpenTherm® (T4R/T4M) compatible control.
- Flip-up wiring platform for easy wiring.
- User Menu Functions: Heating schedule, Date and time setting, Optimisation, Lock function, OpenTherm® alerts (T4M only).
- Installer Menu Functions: Language selection, Cycle rate, Upper/Lower set point limit adjustment, Minimum ON time, Daily/weekly/5+2 schedule option, 4 or 6 periods per day, Wired remote sensor, Fail safe mode, Clock format, Daylight saving time change (DST), Temperature display offset, Factory reset, Binding (T4R only).
Thermostat Display/Button Layout
The thermostat display shows setpoint periods, current time/timer, menu items, alert/fault status, room temperature, setpoint temperature, heat demand, and low battery status. It also indicates wireless signal strength (for T4R only) and schedule status.
Navigation is done via buttons for Menu (☰), Confirm (✖), and Cancel (✗). Other functions include Timed override (⏚), Standby mode, Home screen (⌂), and Away mode (?).
Reference to the Icons:
- Status Icons:
- Schedule On: Programmed schedule is active.
- Schedule Override: Active until the next scheduled period or timed override duration ends.
- Schedule Off: Programmed schedule is turned off.
- Low Battery: Power is approximately 10% (flashes when critically low).
- Heat Demand: Room temperature is below setpoint, indicating heating is required (boiler activity may occur).
- Wireless Signal: Thermostat (T4R only) is connected to the Receiver Box (?).
Receiver Box Interface
The Receiver Box features a Status LED indicating communication with the thermostat and binding mode. It also has a Manual override button and a Reset/Delete binding button.
Specifications
T4/T4M/T4R Thermostat
| Parameter | Details |
|---|---|
| Control form | Fuzzy Logic |
| Room temperature display range | 0 °C to 50 °C |
| Dimensions (w x h x d) | T4/T4M: 136 x 97 x 28 mm T4R (Wireless): 136 x 98 x 62 mm |
| Time display | 24 hour or 12 hour AM/PM format |
| Time keeping accuracy | +/- 10 mins per year |
| Program | 5+2, weekly, or daily schedule with 4 or 6 daily time and temperature level changes |
| Time setting resolution | 15 minute steps |
| Sensing element | 10k(@25 °C) NTC thermistor |
| Temperature Setting range | Program: 5 to 35 °C OFF: 5 °C |
| Power | 2 x AA batteries |
| Wiring | T4 (wired) and T4M (OpenTherm) terminal block capable of accepting wires up to 1.5 mm² |
| RF communication band | ISM (868.0-868.6) MHz, 1% duty cycle |
| Max. power | 25mW |
| Protocol | Encrypted |
| Comm. Range | 30m in residential building environment |
| Comm. Technology | Short, high rate transmissions to minimise air time and avoid collisions |
| Receiver class R.E.D. | RX Cat 2 (ETSI EN300 220-1 version 1.3.1) |
Receiver Box
| Parameter | Details |
|---|---|
| Power | 230VAC |
| Electrical rating | 230V~, 50..60Hz, 0.5A to 5A resistive; 0.5A to 3A inductive (0.6 pf) 24V~, 50..60Hz, 0.5A to 5A resistive; 0.5A to 3A inductive (0.6 pf) |
| Cycle rate | Selectable by application (see installer set up) |
| Wiring | Terminal block capable of accepting wires up to 1.5 mm² |
| Wire access | From back via large wall box opening. From bottom with cable clamps. Mains wiring - left, Low voltage wiring - right. |
| Dimensions (w x h x d) | 110 x 110 x 40 mm |
| IP class | 30 |
Environmental and Standards
| Parameter | Details |
|---|---|
| Operating temperature range | 0 to 40 °C |
| Shipping and storage temperature | -20 to 55 °C |
| Humidity range | 10 to 90% rh, non-condensing |
| EMC | 2014/30/EU |
| LVD | 2014/35/EU |
| R&TTE | 1995/5/EC |
| ErP | Class IV (+2%), (EU) 811/2013 (T4) Class V (+3%), (EU) 811/2013 (T4R) Class VI (+4%), (EU) 811/2013 (T4M) |
Honeywell declares that this thermostat is in compliance with the essential requirements and other relevant provisions of Directive 2014/53/EU.
Installer Menu Options
To enter the Installer menu, press the ☰ button and then navigate using the +/- buttons until the display changes (approx. 3 seconds).
| Specific Applications | Setting | What do you need to change? |
|---|---|---|
| Heating | CpH (cycle per hour): 6 Minimum on Time (min): 1 |
Note: a. To change cycle per hour b. To change minimum ON time No action required for Gas Boilers (30kW). |
| Oil Boiler | CpH: 3 Minimum on Time (min): 4 |
a. Set minimum ON time to 4 minutes. b. Set cycle per hour to 3. |
| Thermal Actuator | CpH: 12 Minimum on Time (min): 1 |
Set cycle per hour to 12. |
| Zone valve | CpH: 6 Minimum on Time (min): 1 |
No actions required. |
Special Features
| Feature | Description |
|---|---|
| OpenTherm® | By connecting the T4M to an OpenTherm® appliance, various specific data can be viewed, depending on what the appliance is providing. |
| Heat range | The normal lower temperature limit of 5 °C can be increased up to 21 °C to protect vulnerable inhabitants (elderly, children, disabled). The normal upper temperature limit of 37 °C can be reduced down to 21 °C to save energy, useful for rental properties. |
| Schedule options | The thermostat defaults to 5+2 schedule (weekday/weekend). It can be changed to 7-day (different schedule each day) or 1-day (same schedule every day). |
| External temperature sensor (only for wired versions) | An external sensor can be fitted to control temperature from another room. It reads the sensor every minute and can be connected up to 50 meters away. Useful for public areas where tampering might occur. |
| Optimisation (optimum start, optimum stop and delayed start) | Optimum Start: Learns how long the system takes to reach the desired temperature and turns heating on earlier to ensure comfort at the scheduled time. Optimum Stop: Saves energy by switching off slightly earlier than programmed if the home is already at temperature. Delayed start: Saves energy by slightly delaying heating start based on the difference between scheduled and actual room temperature. |
| Clock setting | Change display format (default 24hr) and adjust time and date. |
| Temperature offset | If the thermostat is in a hot/cold location, the displayed temperature can be adjusted by +/- 1.5 °C to match other appliance displays. |
| Binding (only for T4R) | Menu to bind the Thermostat and Receiver box, test RF signal strength, and clear existing bindings. |
| Reset | Resets the thermostat to factory default settings and restores the schedule to default. |
| Failsafe | If the temperature sensor fails (T4, T4M) or wireless communication is lost (T4R), the device cycles the demand 20% On / 80% Off. |
Menu Item Settings
| Menu item | Default | What do you need to change? |
|---|---|---|
| 1LA: Language | 1=English | 1=English, 2=Dutch, 3=French, 4=German, 5=Spanish, 6=Italian |
| 2CR: Cycle rate | 6 | 3,6,9,12 |
| 3OT: Min on time | 1 | 1,2,3,4 or 5 minutes |
| 4LL: Lower Temperature | 5 | 5 °C to 21 °C |
| 5UL: Upper Temperature | 25 | 21 °C to 35 °C |
| 6SO: Schedule options | 5+2 | 1= 7 day (different schedule each day of the week) 2= 5+2 (weekday + weekend schedule) 3= 1 day (same schedule every day of the week) |
| 7NP: Number of periods | 4 | 4 or 6 number of heating periods per day |
| 9LC: Fail safe mode | 0 | 0= Deactivated 1= Activated |
| 10BL: Backlight | 1 | 0= Deactivated 1= Activated (only on demand) |
| 11CL: Clock format | 0 | 0= 24h 1= 12h (AM/PM) |
| 12DS: Daylight saving time change | 1 | 0= Deactivate Daylight saving time change 1= Automatically change time during DST |
| 13TO: Temperature offset | 0 | -1.5 °C to + 1.5 °C |
| 15SD: Restore schedule | 0 | 1= Reset the default schedule |
| 16FS: Restore factory settings | 0 | 1= Reset the device to factory settings |
Dimensions
T4, T4M Thermostat: 136 mm (width) x 97 mm (height) x 28 mm (depth). Weight: 260 grams.
T4R Thermostat: 136 mm (width) x 98 mm (height) x 62 mm (depth). Weight: 260 grams.
Receiver Box: 110 mm (width) x 110 mm (height) x 40 mm (depth). Weight: 200 grams.
Installation
Safety First: Always ensure mains power is switched OFF before accessing wiring. Before removing an old thermostat, take a picture of its wiring as a reference.
Thermostat Placement: The T4 thermostat should not be placed near draughts, in direct sunlight, or near heat sources. It should be mounted at least 1.2 - 1.5 meters from the floor.
Prepare Receiver Box (T4R only)
Needed during installation:
- Cable with 2 wires from boiler to Receiver Box (R4H910RF1004).
- The Receiver Box requires 230V power.
Location: Find a suitable location near the boiler, at least 30cm away from any metal objects, including wall boxes and boiler housing.
Accessing Terminals: Loosen the front screw to remove the cover or tighten it when the cover is back in position.
Install Receiver Box (T4R only)
A. Wall box or Rear wiring: Hinge open the terminal block flap to access the cables and wall box screw holes.
B. Surface wiring: Hinge open the terminal block flap to access the cables and wall box screw holes.
C. Replace cover: Locate the hinges at the top of the cover and wall plate, close the cover, and secure with the screw.
Complete Installation (T4R)
Turn mains power ON to the heating application and the receiver box. After powering up, the status LED on the Receiver Box should be steady GREEN (?). Press the manual override button to check if the boiler switches ON. The button LED lights should turn GREEN (?).
Install Thermostat (T4 and T4M only)
A. Wall plate: Using a screwdriver, open the wall plate terminal cover to connect wires.
B. Surface wiring: Connect wires according to wiring diagrams and clip the cover closed.
C. Place thermostat: Attach the thermostat to the wall plate when finished.
Power Up the Thermostat (T4 and T4R only)
Remove the battery tab and clip the thermostat onto the wall-plate.
Setup and Configuration
After power up, the language selection is displayed on the thermostat's screen. Press +/- to select language and ☰ to confirm.
Then, press +/- to set date, time, and clock format, and ☰ to confirm.
BINDING (T4R only)
The T4R thermostat wireless kit comes pre-bound from the factory. Binding is only required if the T4 thermostat or Receiver box is replaced, or if binding data is incorrect or missing.
To bind/rebind:
- Reset Receiver Box: If the Receiver box has been bound before, press the pinhole with a small pin for approximately 3 seconds to reset binding. LEDs will flash amber momentarily.
- Put Receiver box into binding mode: Press the button for 3 seconds. The LED will flash amber.
- Enable binding on thermostat: Enter the binding menu by pressing and holding the ☰ button for 3 seconds, then press the - button. Change parameter 14A to 1 and press ☰ to confirm.
- Successful binding: The [Wi-Fi symbol] icon will appear on the thermostat's screen. The Receiver box status LED will show steady green.
Wiring Diagrams
The following diagrams illustrate wiring configurations for different boiler types and thermostat models. It is recommended to consult a qualified installer for electrical work.
Wiring (T4 and T4M only)
Basic 230V Boiler: Connects the thermostat to a basic 230V boiler. Includes connections for permanent live (if required), L, N, and thermostat terminals (A, B, C, T, S).
Combi-Boiler: Connects the thermostat to a combi-boiler. Similar terminal connections as basic boiler.
2-Port Zone Valve: Connects the thermostat to a 2-port zone valve system (e.g., V4043). Includes connections for L, N, and thermostat terminals (A, B, C, T, S), with a connection to the zone valve.
OpenTherm Boiler: Connects the T4M thermostat to an OpenTherm boiler. Features polarity-free connections for OpenTherm communication.
Wiring (T4R only)
Basic 230V Boiler: Connects the Receiver Box to a basic 230V boiler. Includes connections for 230V power (L, N), and Receiver Box terminals (NL, A, B, O/T, O/T).
Combi-Boiler: Connects the Receiver Box to a combi-boiler. Similar terminal connections as basic boiler.
2-Port Zone Valve: Connects the Receiver Box to a 2-port zone valve system. Includes connections for 230V power (L, N), and Receiver Box terminals (NL, A, B, O/T, O/T), with a connection to the zone valve.
Troubleshooting
Troubleshooting – T4 and T4M only
| Problem Display | Possible Cause | Remedy |
|---|---|---|
| Thermostat display is blank | Batteries exhausted, installed incorrectly, or tab hasn't been removed. | Unclip thermostat from wall and check battery installation; replace batteries if necessary. |
| Display shows ⚠️ (only for T4) | Battery power critically low. | Unclip thermostat from wall and replace batteries immediately. |
| Display shows ⚠️ | Faulty temperature sensor. | Replace thermostat or check wiring to remote temperature sensor if fitted. |
| Thermostat shows heat demand ? but boiler doesn't respond | a. Boiler water already at temperature. b. Faulty wiring connection. |
a. Normal behaviour - wait for water temperature to drop. b. Check wiring at thermostat and boiler terminals. |
Troubleshooting – T4R
| Problem Display | Possible Cause | Remedy |
|---|---|---|
| Thermostat display is blank | Batteries exhausted, installed incorrectly, or tab hasn't been removed. | Pull thermostat from wall bracket or table stand and check battery installation; replace batteries if necessary. |
| Display shows ⚠️ | Battery power critically low. | Pull thermostat from wall bracket or table stand and check battery installation; replace batteries if necessary. |
| Display shows ⚠️ | Faulty temperature sensor. | Replace thermostat or check wiring to remote temperature sensor if fitted. |
| Thermostat shows heat demand ? but boiler doesn't respond | a. Boiler water already at temperature. b. Faulty wiring connection. |
a. Normal behaviour - wait for water temperature to drop. b. Check wiring at thermostat and boiler terminals. |
| Thermostat displays shows ⚠️ and Receiver Box ? LED is flashing RED | Wireless communication with Receiver Box is lost. | Move thermostat to a location where wireless communication is reliable. |
| Thermostat displays shows ⚠️ and Receiver Box ? LED is flashing OFF | Thermostat and Receiver Box not bound. | Move thermostat to a location where wireless communication is reliable. |
| Receiver Box LED is flashing ORANGE | Receiver Box is in bind mode. | Wait for bind mode to time out (3 min) or bind a Thermostat. |
Ordering Specification
| Description | Model | EAN code | Literature |
|---|---|---|---|
| T4 wired thermostat | T4H110A1021 | 5025121381215 | All packaging contains 6 languages: English, Dutch, French, German, Italian and Spanish. |
| T4 wired thermostat for OpenTherm boilers | T4H310A3032 | 5025121381208 | |
| T4 wireless thermostat | Y4H910RF4003 | 5025121381079 |
