Intergas with Evohome/Opentherm

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I installed Evohome over 2 years ago. I am now looking to replace a 16 year old boiler with either a Viessmann, ATag or Intergas product using an Opentherm connection. I know that the Viessmann 100 needs a HW junction box for HW priority; the Atag needs an EBus to Opentherm converter and Intergas only needs the Honeywell Opentherm bridge.

I am leaning towards the Intergas but there are reports on various forums that the Intergas boiler has problems coping with Evohome multi-zoning (I have 12 zones and 19 radiators). There are also suggestions that it would be better just leaving my existing 2 BDRs in place (on a 'S' unvented cylinder plan) with an Intergas boiler with weather compensation. I assume that in this configuration the boiler would provide HW priority to heat the unvented cylinder?

Grateful for any advice on boiler choice/configuration would be appreciated. Thanks.
 
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It works well, but doesn't appear to modulate with multiple zones. Investigations and upgrades are in progress.

In the mean time (as OpenTherm is an upgrade anyway) you can use weather comp and Evohome together.
 
Thanks Dan. When you say 'in progress' any idea of the likely timescale? Any known problems with Atag and Evohome Opentherm?
 
No idea on time scales.... It might already be here. We're waiting to find out from Holland.

Atag should work, but personally, I'd stick with the Eco RF.
 
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No idea on time scales.... It might already be here. We're waiting to find out from Holland.

Atag should work, but personally, I'd stick with the Eco RF.

As I have an Oso 250L unvented cylinder, I think that the boiler that I would need would be the Intergas Compact HRE SB.
 
Eco rf can be used as a system boiler, comes with a 10 year warranty and also the inTouch system for remote diagnosis as well as thermostat control if you're happy with a single heating zone (it will do two zones eventually).

I have the rf at home with an unvented cylinder, Evohome which I jump between OpenTherm and weather comp depending on what I'm experimenting with.
 
Eco rf can be used as a system boiler, comes with a 10 year warranty and also the inTouch system for remote diagnosis as well as thermostat control if you're happy with a single heating zone (it will do two zones eventually).

I have the rf at home with an unvented cylinder, Evohome which I jump between OpenTherm and weather comp depending on what I'm experimenting with.

Knowledge is power. I hadn't appreciated that configuration of the Eco Rf in this way was possible. Will it work with 'S' plan or am I into a system reconfiguration? How will the boiler firmware be updated to solve the current Evohome/Opentherm multi-zoning issues? Sorry to ask so many questions but when it comes to CH, I am rather outwith my knowledge comfort zone.
 
S plan will work fine, hot water priority even better, but your installer will know how to sort that.

Firmware updates would need a new PCB, and I'm not sure how happy IGUK will be doing that under warranty when there is a a viable alternative to the controls.
 
Firmware updates would need a new PCB,

Eek. At this point, I am beginning to wonder whether the Eco Rf plus weather compensation with control via BDRs is a more sensible option? Given the savings that I am already accruing from Evohome, any additional savings will primarily be the result of a more efficient boiler. Thanks again for all your advice.
 
Just a further thought from the depths of my old mind. If the CH motorised valve is disabled/open or removed, then surely multi-zoning doesn't come into play? Is this a way around the Intergas/Evohome issue?
 
The problem is that the boiler or Evohome (no one really knows which at the moment) doesn't cope with modulating the setpoint with multiple zones.

My theory is that there is too much data and the boiler PCB can't interact quickly enough with the OpenTherm bridge so it drops its knickers and runs at whatever the maximum setting is.

Eliminating the heating zone valve is not going to affect that if you have hr92's installed.
 
That being said even with a setpoint of 55 degrees in mine the boiler spends most of its life either off and pumping the existing heat around, or on its minimum kw output.
 
so are we concluding here that intergas boilers cannot currently handle multizoning via Opentherm? Is there an alternative multizone control system that would work with my Intergas HRE40 system boiler? Be nice to use the Opentherm functionality if at all possible. Would an Intergas external sensor make much of a difference (I have one ready to fit but unsure how it works!).
 

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