The Efficient Home Forum

Hope anyone can help with the following question.

Our old boiler is on its last legs. We have Evohome running 6 zones. We are looking at purchasing an Atag boiler, which we know are more expensive but we are looking to use Opentherm with our next boiler and we don't want to use third party or warranty breaking adapters, such as those needed for Worcester Bosch and Vaillant.

Therefore we are leaning towards the Atag. My question is should we use it with Opentherm, weather compensation or, if it's possible, both?.

From looking at the installation manual it's not overly clear whether both WC and OT can be used at the same time, or even if it's worth it. Does anybody here have any real world experience that they could share?

Is there a particular reason you are leaning towards Atag? Intergas is a technically better OpenTherm boiler and its OpenTherm implementation is flawless.

As for your question, evohome is an ErP Class 5 or Class 8 control when you use it with an R8810 OpenTherm Bridge so really no need to use an outdoor sensor with either Atag or Intergas.

Thanks for coming back.

Intergas is on my radar as well, the only problem I have with that is what seems to be a lack of decent installers in my area. A couple of them that are credited as being approved by Intergas have no acknowledgment of that on their own websites. I will be completing more research before committing though.

Your answer is what I suspected, its just really not clear when you research Weather compensation and Load compensation which is better to have. Kind of worked out that they are doing essentially the same job but coming at it from a different angle, thanks for confirming that to me.

Intergas doesn't need an accredited installer... Any Gas Safe Registered installer is able to fit Intergas boilers and as long as the terms and conditions are followed the manufacturers warranty on the Intergas boilers would be upheld.

The ErP definition for heating controls is widely available on the internet, but unless you are a heating installer then you might not know exactly what they mean.

Most thermostat packaging should now show the relevant ErP rating on them (ErP Class 1 & 4 being the worst thermostats and ErP Class 5, 6 & 8 being the best thermostats for OpenTherm boilers).

Ok, the need just for a Gas Safe installer gives me another reason to bore my wife with boiler talk now then!. We are lucky to have quite a few Gas Safe installers nearby so I will be bending their ears in due course. Thanks for your help.

Hi,
I have just had an Intergas Xtreme 36 installed and it works a treat with my evohome with opentherm bridge if that helps. The boiler seems to be condensing all of the time.

mineshshah73 wrote:Hi,
I have just had an Intergas Xtreme 36 installed and it works a treat with my evohome with opentherm bridge if that helps. The boiler seems to be condensing all of the time.

Hi I am considering the extreme 36 also because of the excellent modulation capability and opentherm compatbility and highest DHW flow , but I am concern about the noise at 58 dB, how have you found the noise in real operation