Honeywell Home T4M Thermostat
Programmable Modulating Thermostat - Quick Start Installation Guide
Introduction
This guide provides quick start instructions for the Honeywell Home T4M Programmable Modulating Thermostat. It is compatible with OpenTherm appliances only and not compatible with 230V boilers, zone valve applications, or 230V electric heating.
Compatibility: OpenTherm appliances only.
Not Compatible With: 230V boilers, zone valve applications, 230V electric heating.
Installation in 3 Steps
- Wire the Thermostat
- Power Up and Test
- Configure the System
Safety Information
⚠️ Must be installed by a competent person.
⚠️ To ensure your safety, make sure the mains power is switched OFF before accessing wiring.
To prevent a short circuit from a loose wire:
- When using multi-core cables: Only remove enough outer insulation to allow secure fixing of the cores into the terminal block.
- When using single core cables: Secure them together with a cable tie as close as possible to the terminal block.
Step 1: Wire the Thermostat
Find a suitable wall location away from draughts, direct sunlight, or other heat sources, and where cables can be run from the boiler to the thermostat. Ensure cables are between 1.2m and 1.5m in length.
A) Prepare the Wallplate
Separate the wallplate from the thermostat. Using a screwdriver, open the wallplate terminal cover to connect wires.
B) Connect Wires
Connect wires according to wiring diagrams and clip the cover closed. Ensure wire gauge is between min 0.25mm² and max 1.5mm², with a maximum exposed conductor length of 6mm.
Thermostat Wiring:
- Terminals: A, B, C, T, T, S, S
OpenTherm Boiler Wiring:
- Terminals: 230V L, N, OT, OT (OpenTherm connection is polarity-free).
Step 2: Power Up and Test
Power up the Heating System and perform a quick functional test on the thermostat to check that it switches the boiler.
- Press the [+] button to increase the temperature to maximum. Check that the boiler switches on and the heat demand icon ? on the thermostat is displayed.
- Now press the [-] button to decrease the temperature to minimum. Check that the boiler switches off and the heat demand icon ? on the thermostat also goes off.
Step 3: Configure the System
Specific settings for the thermostat and heating system can be configured in the advanced menu.
To enter the advanced menu, press and hold the [Back] and [+] buttons together until the display changes (approx. 3 seconds).
- A) Navigate Parameters: Press [Up Arrow] and [Down Arrow] buttons to navigate through the parameter list.
- B) Change Parameter: Press [+] and [-] buttons to change a parameter.
- C) Save Change: Press [✓] button to save the change (or press [Back] to cancel the change).
- D) Exit Menu: Press [Back] button to exit the advanced menu and save any changes.
Parameters
| N° | Description | Settings (default in bold) |
|---|---|---|
| 1:LA | Language | 1 = EN, 2 = NL, 3 = FR |
| 2:CR | Cycle Rate | 6 |
| 4:LL | Lower Temperature Limit | 5-21 (°C) |
| 5:UL | Upper Temperature Limit | 21-35 (°C) |
| 6:SO | Schedule options | 1 = 7 day (different schedule each day of the week) 2 = 5 + 2 day (weekday + weekend schedule) 3 = 1 day (same schedule every day) |
| 7:NP | Number of periods per day | 4 or 6 |
| 8:SS | Wired Remote Sensor | 0 = No Remote Sensor, 1 = Wired Remote Sensor |
| 9:LC | Fail Safe mode | 0 = Boiler off, 1 = Boiler 20% on / 80% off |
| 10:BL | Backlight | 0 = Off, 1 = On (only on demand) |
| 11:CL | Clock Format | 0 = 24 hr, 1 = AM/PM |
| 12:DS | Daylight Saving time change | 0 = Off, 1 = Auto |
| 13:TO | Temperature Display Offset | +/-1.5°C |
| 15:SD | Restore Schedule Defaults | 0, 1 = reset |
| 16:FS | Restore Factory Settings | 0, 1 = reset |
| 17:OP | Optimisation | 0=Disabled, 1=Enabled |
OpenTherm Data ID's
An OpenTherm boiler can report alerts back to the Thermostat. You can view these in the 'OpenTherm boiler alerts' menu. The OpenTherm Data ID's appear after the installer parameters.
| N° | Description | Settings (default in bold) |
|---|---|---|
| OT1 | Low load control | 0 = Off, 1 = On |
| OT2 | Control setpoint | 5-99°C |
| OT3 | Supply water temperature | 5-99°C |
| OT4 | Return water temperature | 5-99°C |
| OT5 | Max. supply water temperature | 5-99°C |
| OT6 | Hot water temperature | 5-99°C |
| OT7 | Hot water setpoint | 5-99°C |
| OT8 | Actual power | 0-99% |
| OT9 | Water pressure | 0.0-9.9 |
| OT10 | OTC control | 0 = Off, 1 = On |
| OT11 | OTC curve | 4-40 (16) |
| OT12 | Room compensation | 0 = Off, 1 = On |
Troubleshooting
| What's happening? | What it could mean... | How to fix it... |
|---|---|---|
| Thermostat display is blank | No power to heating system | Check heating system is powered. |
| Faulty wiring connection | Check wiring at thermostat and boiler terminals. | |
| Display = | Faulty temperature sensor | Replace thermostat or check wiring to remote temperature sensor if fitted. |
| Thermostat shows heat demand but boiler doesn't respond | Boiler (water) already at temperature | Normal behaviour - wait for water temperature to drop. |
| Faulty wiring connection | Check wiring at thermostat and boiler terminals. |
Compliance and Manufacturer Information
Conforms to protection requirements of the following directives:
- EMC: 2014/30/EU
- LVD: 2014/35/EU
The full text of the EU declaration of conformity is available at the following internet address: https://hwllhome.co/DoC
ErP: Class V (+3%), (EU) 811/2013
WEEE Directive 2012/19/EU - Waste Electrical and Electronic Equipment directive. At the end of the product life, dispose of the packaging and product in a corresponding recycling centre. Do not dispose of the unit with usual domestic refuse. Do not burn the product.
Manufacturer:
Resideo Pittway Sarl, Z.A. La Pièce 4, 1180 Rolle, Switzerland
Website: www.resideo.com
Country of origin: UK
©2020 Resideo Technologies, Inc. All rights reserved. The Honeywell Home trademark is used under license from Honeywell International Inc. This product is manufactured by Resideo Technologies, Inc. and its affiliates.
hwllhome.co/DoC
