Honeywell T4M Programmable Modulating Thermostat Installation Guide

June 6, 2024
Honeywell

T4M Thermostat
Programmable Modulating Thermostat

Quick Start Installation Guide

Compatible with OpenTherm appliances only.
Not compatible with 230V boilers, zone valve applications or 230V electric heating.

Installation in 3 steps…

Must be installed by a competent person.
To ensure your safety make sure the mains power is switched OFF before accessing wiring.

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.


A) Separate the wallplate from the thermostat, and using a screwdriver open the wallplate terminal cover to connect wires.| B) Connect wires according to wiring diagrams and clip the cover closed.

OpenTherm Boiler

**** 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.

Power Up and Test

Power Up the Heating System and do a quick functional test on the thermostat to check that it switches the boiler.

Configure the System

Specific settings for the thermostat and heating system can be configured in the advanced menu.
Press and hold and then buttons together until the display changes (approx. 3sec).


A) Press√ and buttons to navigate through the parameter list| B) Press+ and- buttons to change a parameter
C) Press√ the button to save the change (or press to cancel the change)| D) Press the button to exit the advanced menu and save any changes

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 IDs appear after the installer parameters (see the table above).

Description  Settings (default in bold)
Low load control 0 = Off, 1 = On
Control setpoint 5 – 99°C
Supply water temperature 5 – 99°C
Return water temperature 5 – 99°C
Max. supply water temperature 5 – 99°C
Hot water temperature 5 – 99°C
Hot water setpoint 5 – 99°C
Actual power 0 – 99%
Water pressure 0.0 – 9.9
OTC control 0 = Off, 1 = On
OTC curve 4 – 40 (16)
Room compensation  0 = Off, 1 = On

Parameters

Description I- Settings (default in bold)
Language 1= EN
Heating Cycle Rate (cps) 3 (oil boiler / thermal actuator)

6 (gas or combi boiler / zone valve) 9 12
| Minimum on time| 1- 5 (mins) (set to 4 mins for oil boiler)
| Lower Temperature Limit| 5 – 21 (°C)
| Upper-Temperature Limit| 21 – 35 (°C)
| Schedule options| 1= 7 days (different schedule each day of the week)
2 = 5 + 2 day (weekday + weekend schedule)
3 = 1 day (same schedule every day)
| Number of periods per day| 4 or 6
| Fail Safe mode| 0 = Boiler off, 1 = Boiler 20% on / 80% off
| Backlight| 0 = Off, 1 = On (only on demand)
| Clock Format| 0 = 24 hr, 1 = AM/PM
| Daylight Saving time change| 0 = Off, 1 = Auto
| Temperature Display Offset| +/-3°C
| Restore Schedule Defaults| 0, 1 = reset
| Restore Factory Settings| 0, 1 = reset
| Optimisation| 0 = Disabled, 1= Enabled

Troubleshooting

What’s happening? What it could mean… How to fix it…
The thermostat display is blank Faulty wiring connection Check heating

system is powered
Faulty wiring connection| Check wiring at thermostat and boiler terminals
Display =| Faulty temperature sensor| Replace thermostat or check the wiring to remote temperature sensor if fitted
The thermostat shows heat demand but the boiler  doesn’t respond| Boiler (water) already at temperature| Normal behavior – wait for water temperature to drop
Faulty wiring connection| Faulty wiring connection Check wiring at thermostat and boiler terminals

Conforms to protection requirements of the following directives:
EMC: 2014/30/EU and 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 center. Do not dispose of the unit with the usual domestic refuse. Do not burn the product.

www,resideo.com
Pittway Sarl, Z.A. La Pièce 4,
1180 Rolle, Switzerland
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.

References

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