The Efficient Home Forum

We really love OpenTherm at The EVOHOME Shop and we thought it would be great if we could have a list of all the gas boilers that have an OpenTherm connection!

So the following boilers have an OpenTherm boiler connection... When we have tested these with Honeywell OpenTherm thermostats, our comments are in brackets.

Intergas ECO RF (tested and fully OpenTherm compliant)
Intergas HRE (tested and fully OpenTherm compliant)
Intergas Rapid (tested and fully OpenTherm Compliant)
Intergas Rapid Plus (tested and fully OpenTherm Compliant)

Ideal Logic
Ideal Logic+
Ideal Vouge Gen 1
Ideal Vouge Gen 2

Viessmann 100 Series (tested but boiler flow temp will go to maximum unless 3rd part OpenTherm controls have a maximum flow temperature Control ID)

I will update the list above as more are tested.

Kindest regards,

Richard Burrows
The EVOHOME Shop Team

Seems the Vaillant with VR33 is compatible looking at other people's experiences online.

I'm still researching replacement boilers and wanting a Viessmann, but the OT overriding the Max temps of the boiler is killing this for me. Can't see a way to circumvent.

The problem with all of this is that the OpenTherm protocol is supposed to be a way of combining any OpenTherm boiler and any OpenTherm controls... The reality is that should a boiler manufacturer make one of the OpenTherm Data ID's (such as max flow temperature) a required element of the controls and then the OpenTherm boiler doesn't have this as a manually adjustable parameter on the boilers settings, the full flow temperature range of the boiler would be used.

This is the issue is with the Viessmann 100 series boiler, as the max flow temp (OpenTherm Data ID 57) is required to be set by the 'master controls' and when it is not set, OpenTherm Data ID 1 will use the full temperature range from 0-100 degrees... If you compare this to the Intergas boilers, you are able to set the max flow temp manually on the boiler if the OpenTherm controls don't and then the control range up to this point is used.

Manufacturers should be listing when they have additional OpenTherm Data ID's that need to be set by the controls, to rule out any incompatibilities with OpenTherm controls...

Hi

Is this list updated since the original post in 2016?

I was looking to buy Viessmann + Evohome but the max temp issue means I am not going with Viessmann

FWIW, I've been running off an Intergas boiler for around 4 years with no issues so far.

The only problem I had was finding a plumber/heating engineer who a) had heard of opentherm and b) would touch any boiler that supported it.

May be different where you live though ....

avinash wrote:Hi

Is this list updated since the original post in 2016?

I was looking to buy Viessmann + Evohome but the max temp issue means I am not going with Viessmann

No unfortunately the post has not been updated... Intergas will always be our recommended boiler brand due to the way they seamlessly implement OpenTherm on their boilers.

I'm planning to use Honeywell EvoHome with the R8810A1018 Wireless OpenTherm Bridge to connect to a Worcester Greenstar 8000 Life 30kw System Boiler installed with a Worcester Easy Control Adapter For Open Therm Compatibility.

Will this be fully compatible?

No I don't think so... The adaptor works the other way making Worcester controls work on an OpenTherm boiler, not the other way around.

Hello,

I'm planning to get an Ideal Vogue Max combi boiler and am considering getting Evohome and an Opentherm bridge - will these work well together? The Ideal documentation says that it is Opentherm compatible, but I'm wary of the sorts of issues that I've read about with e.g. Viessmann boilers.

Thanks for any help that you can give...

What was the reason for getting the Ideal Vouge? Ideal are no where near as good with their OpenTherm implementation, where Intergas with their Xclusive is one of the best boilers that works with evohome.