OpenTherm Capable Boilers and Controls

OpenTherm Logo
OpenTherm Logo

Shown below are a list of OpenTherm capable / compatible manufacturers and boilers. These OpenTherm Boilers / OpenTherm capable boilers have integrated OpenTherm unless specified otherwise in brackets. For more info on “What is OpenTherm?” at the  OpenTherm Association. You can also see our OpenTherm Capable Controls shown further down the page.

For homeowners: what OpenTherm means see the following page: Modulating ‘A Rated’ Boilers with Smart Modulating Thermostats

What is OpenTherm?

Wikipedia: OpenTherm (OT) is a standard communications protocol used in central heating systems for the communication between a central heating boiler and a thermostatic controller. A two way communications interface, usually in the form of a slave and master device.

As a standard, OpenTherm is independent of any single manufacturer. A controller from manufacturer A can in principle be used to control a boiler from manufacturer B. However, OpenTherm controllers and boilers do not in fact always work properly together. The OpenTherm standard comprises a number of optional features and some devices may include manufacturer-specific features. The presence or absence of such features may impair compatibility with other OpenTherm devices.

OpenTherm History?

OpenTherm was originally created by Honeywell and was sold to the OpenTherm Association on November 1996 for one British Pound. This was no doubt to make the standard independent of any manufacturer.

Modulating Control

Unlike room thermostats that simply tell the boiler when to turn on and off (non modulating graph below) , a modulating control (see modulating graph below) tells the boiler the exact target / set point temperature that is required to be achieved. So as the current temperature starts getting closer to the set point temperature, the boiler starts reducing the flow temperature to match the required demand.

Non modulating thermostat

Modulating Thermostat Graph

OpenTherm Advanced setups

OpenTherm is easier to use on combi boilers. The reason for this is that there is no hot water cylinder to worry about, heating to the correct temperatures as required by legionalla prevention(recommended 60 degrees), as OpenTherm can reduce flow temperatures to below 60 degress. So, on system and regular boilers that have opentherm, in order to also work with hot water cylinders, cylinder temperature reporting must be present in some form. This allows the OpenTherm to fire at high temperature just for the hot water. Note, is is advised that in this setup there is priority to the hot water system, otherwise higher temperatures may reach the radiators when you don’t want them to.

OpenTherm Compatible Boilers

For Manufacturers: If your boiler model is not in this list, please contact us via our contact form or via twitterAdditional Information

Vaillant Ecotec 4XX Series requires additional steps. Please see following thread: https://www.automatedhome.co.uk/vbulletin/showthread.php?4715-Evohome-Opentherm-v-Evohome-Boiler-Outside-Weather-Compensation&p=28823&viewfull=1#post28823

BrandModelAdditional Info
alpha logoAlpha Heating Innovation

https://www.alpha-innovation.co.uk
BrandModelsAdditional Info
Alpha HeatingE-Tec S
Alpha HeatingE-tec Plus
Alpha HeatingE-tec
Alpha HeatingEvoke
Alpha HeatingIntec GS




Atag Heating Technology
http://atagheating.co.uk
BrandModelsAdditional Info
AtagiC
AtagiC Economiser
AtagiS



Baxi
http://www.baxi.co.uk/
BrandModelsAdditional Info
Baxi100 CombiOpenTherm is Terminals 1 and 2 on the M2 Low Voltage Terminal Block
Baxi200 CombiOpen Therm connecter is labelled 'Bus'
Baxi400 CombiOpen Therm connecter is labelled 'Bus'
Baxi600 CombiOpen Therm connecter is labelled 'Bus'



Daikin
https://www.daikin.eu/
BrandModelsAdditional Info
DaikinD2CND 24KwCombi Boiler
DaikinD2CND 28kwCombi Boiler
DaikinD2CND 35kwCombi Boiler




Ferroli
http://ferroli.co.uk
ModelsAdditional Info
Ferrolii25 Condensing Combination Boiler
Ferrolii29 Condensing Combination Boiler
http://ferroli.co.uk




Ideal Boilers
http://idealboilers.com/
BrandModelsAdditional Info
IdealIndependent + CombiOption Kit may be required
IdealIndependent CombiOption Kit may be required
IdealIndependent SystemOption Kit may be required
IdealLogic Combi+ Combi C
IdealLogic Combi C24, C30, C35 Requires seperate harness kit
IdealLogic Code CombiRequires seperate harness kit
IdealI-mini C24, c30 Requires seperate harness kit
IdealVogue Combi C26,C32, C40
IdealLogic + System(Works with Evohome)
IdealLogic + Heat(Works with Evohome)



ideal commercial logoIdeal Commercial

https://idealcommercialboilers.com/
BrandModelsAdditional Info
Ideal CommercialEvomax
Ideal CommercialImax



Intergas Boilers
http://www.intergasheating.co.uk/
BrandModelsAdditional Info
IntergasIntergas Rapid
IntergasIntergas Rapid Plus
IntergasCombi Compact
IntergasCompact Range
IntergasECO RF
IntergasXtremeDual OpenTherm
IntergasXclusiveDual OpenTherm



keston logoKeston
http://keston.co.uk/
BrandModelsAdditional Info
KestonCombi C30 & C35Requires seperate harness kit
KestonSystem S30
KestonHeat 45 and 55



Main Heating logo Red RGBMain
https://www.mainheating.co.uk
BrandModelsAdditional Info
MainEco Compact Combi 25-30Same accessories as Baxi.




KD Navien
http://www.navienuk.com/
BrandModelsAdditional Info
Navien NCB




Ravenheat
BrandModelsAdditional Info
RavenheatHE30S Compact
RavenheatHE80
RavenheatHE98S Combi




Remeha Boilers
BrandModelsAdditional Info
RemehaAvanta
RemehaQuinta Ace
RemehaQuinta Pro
RemehaGas 110 EcoCommercial




Viessmann
https://www.viessmann.co.uk
BrandModelsAdditional Info
ViessmannVitodens 100W Type WB1A (Connection: X3.3 and X3.4)
ViessmannVitodens 100W Type WB1B (Connection: X21.1 and X21.2)
ViessmannVitodens 100W Type WB1C (Connection: X21.1 and X21.2)
ViessmannVitodens 200-W WB2B 26+ 35 kW (via Expansion Module OT and OT-A8 + _Terminal -10 and +10 are on expansion A8 boiler )
ViessmannVitodens 200-W WB2C, B2HA,B2JA, B2LA (via icm Expander OpenTherm)




Vokera
https://www.vokera.co.uk
BrandModelsAdditional Info
VokeraEvolve C
VokeraEvolve S
VokeraLinea One (via OpenTherm Kit Part_1221179)
VokeraVision Combi (requires control interface 29450143)
VokeraCompact A (requires control interface 29450143)
VokeraVerve_(heating only mode)
VokeraMynute i (heating only mode)
VokeraVision System (heating only mode)
VokeraUnica i
VokeraVibeSystem boiler
VokeraVision C
VokeraLinea HE
VokeraMynute ASystem boiler
VokeraMynute HE
VokeraUnica HE



Opentherm Compatible Boilers List Last Updated: 28/11/2018

OpenTherm Compatible Boilers – Unofficially Compatible

The following boiler models, mostly Vaillant and Worcester Bosch are capable unofficially. Using the mentioned adaptors may invalidate your warranty. However boilers that are out of warranty will have no known problems, as these adaptors are purpose made by the companies themselves for some European countries, where governments have made it compulsory to have OpenTherm.

 

BrandModelAdditional Info

Vaillant
https://www.vaillant.co.uk
BrandModelsAdditional Info
VaillantEcotec Pro [1]
VaillantEcotec Plus_[1][2]
VaillantEcotec Exclusive[1]
VaillantEcofit Pure_[1]
[1] Using un-official VR33 Module Vaillant OpenTherm and VR33
[2] Ecotec 4XX Series requires additional steps.



Glow Worm
https://www.glow-worm.co.uk
BrandModelsAdditional Info
Glow-WormBetacom 1,2,3,4Requires Adaptor
Glow-WormEasicom 1, 2, 3Requires Adaptor
Glow-WormEnergy 35 StoreRequires Adaptor
Glow-WormEnergy CombiRequires Adaptor
Glow-WormEssentialRequires Adaptor
Glow-WormFlexicomRequires Adaptor
Glow-WormUtracomRequires Adaptor
Glow-WormUltimate3Requires Adaptor



Worcester Bosch
BrandModelsAdditional Info
Worcester BoschEMS capable boilers [1]Worcester Bosch and OpenTherm Page
Worcester BoschGreenstar i
Worcester BoschGreenstar i Junior [**]
Worcester BoschGreenstar Si Compact
Worcester BoschGreenstar CDi Compact
Worcester BoschGreenstar CDi Classic [ŒŠí_í_]
Worcester BoschGreenstar Highflow CDi
Worcester BoschGreenstar 12i System - 24i System [*^]
Worcester BoschGreenstar 27i System - 30i System [*]
Worcester BoschGreenstar CDi Classic System [*ŒŠí_í_]
Worcester BoschNote: Worcester Bosch OpenTherm information is very limited, please accept this list as capable, but not yet confirmed. There is also no confirmation of hot water working with OpenTherm
[1] Using un-official Nefit Adaptor
[*] Provided optional integral diverter valve is installed
[**] Manufactured after July 2013
[ŒŠí_í_] Manufactured after 16th January 2007 with software version CF12.10 onwards.
[^] Manufactured after February 2011.



Opentherm Compatible Boilers List Last Updated: 24/11/2018

OpenTherm Compatible Controls

Following are a list of OpenTherm compatible controls. These controls are compatible with Open Therm Capable boilers shown above. Smart Thermostats are listed first. Where an addition tranceiver is required it will be specificied in the brackets. See more info on OpenTherm at the OpenTherm Association.For homeowners: what OpenTherm means see the following post: What is OpenTherm?

Open Therm fact sheet from Honeywell the original creators of OpenTherm:   OpenTherm Fact Sheet

BrandModelReview Page / Info page.Wired / WirelessRadiator ValvesInternet ConnectedHomekitOther
Baxi uSense smart room thermostatNY
Delta DoreTybox Bus OT - 6053056WiredNNN
DraytonWiser Kit 1WirelessYYNHeating Only
DraytonWiser Kit 2WirelessYYNHeating and Hot Water
DraytonWiser Kit 3WirelessYYN3 Zone Support
EsiESRTP4OT Programmable Room ThermostatWiredNNN
HoneywellT87M2018WiredNNN
HoneywellT4MWiredYNNoptional WC curve setting and internal reference - no support for DHW setpoint.
Honeywell T4RWirelessNNNno support for DHW setpoint.
HoneywellLyric T6WiredYYYsupport for DHW setpoint and overnight preheat disable for combi boiler applications.
HoneywellLyric T6RWirelessYYYSupport for DHW setpoint and overnight preheat disable for combi boiler applications.
HoneywellT6R-HWWirelessYYYSupport for DHW setpoint and overnight preheat disable, plus timed hot water control for storage combis and system boilers.
HoneywellEvohomeWirelessYYNRequires R8810
HoneywellCM727WirelessNNNRequired R8810
HoneywellCMS927B1049 Room UnitWirelessNNNRequires R8810
HoneywellCMT937A1011WiredNNN
IdealLogic RF7WirelessNNN
IdealTouch Connect Wifi Combi Control 214217
WirelessNNN
NestSmart Thermostat 3rd GenerationWirelessNYN
NestSmart Thermostat E 3rd GenerationProduct InfoWirelessNYN
RemehaiSenseWired / WirelessNNN
SalusRT520WiredNNN
SalusRT520WiredNNN
SalusRT520RFWirelessNNN
TadoTado Smart ThermostatWired / WirelessYYYRequires Extension Kit
VokeraBeSmartWirelessY
Vokera20050690 Open Therm 7 Day Programmable RF Room ThermostatWiredNNN
VokeraOpenTherm RF Programmer (20050690)WirelessNNN








OpenTherm Compatible Controls Last Updated: 11/11/2018

 

Credits/ Sources / Public Contributors:

Richard Huish

Automatedhome; HenGus, Bruce_Miranda

Steve Todd

John Lockwood

Information Sources: 

https://wifithermostaten.nl/advies/aansluittabellen/aansluittabel-viessmann.html

https://www.vokera.co.uk/wp-content/uploads/2016/02/BeSMART_Installer_Brochure1.pdf

Page Last Updated: 28/11/2018

Leave a Reply

Your email address will not be published. Required fields are marked *

Disclaimer: Information on this website is provided for informational purpose therefore we cannot accept liability for subsequent problems. All repair tasks should be carried out by qualified trades people. We may also receive commission payments when you are taken to external websites and complete purchases from third party sellers, once you leave our site, we cannot be held liable for your purchases.