Which Combi boiler works best with Evohome?

[Ubarrow]

I've had an Evohome system for 7 years now, linked to a thermal store which was heated by a Windhager pellet boiler. There was no interface between the boiler and Evohome, the BDR91 just controlled a pump on the heating side of the thermal store.
We've now moved house to a three bedroom bungalow with a 20 year old boiler plus vented cylinder and an "on twice a day" thermostat.

There are just the two of us and the logic is taking me towards a 30kw Combi boiler. Thinking of Worcester Bosch, Baxi, Veissmann or Vallant.

They all seem to boast wifi capability and some have smart thermostats etc sold alongside them but as far as I can see none offer the capability of Evohome.

So, assuming I install Evohome (which I am happy to do having had no problems with my previous system) which is the best combi boiler to work with it? I've seen some issues reported with the latest Worcester Bosch range but this may simply be because they are the most popular boiler. I don't suppose any of them actually interface wirelessly with Evohome? I can't find this capability mentioned anywhere.

It would be great to hear from some installers who have actually fitted these............

Thanks in advance

Peter

[filbert]

There are a few threads covering this already (see below). Intergas is often mentioned.

I'm in the same boat, except that I have Evohome already installed.

My problem is finding an installer. The guy who installed Evohome is a Worcester guy (not surprising as we live just outside the City). I've had a couple of recommendations for other installers but I'm hesitating and am inclined to stay with the guy I know and who has been reliable - on the plumbing side, that is, we've had no need for any support for Evohome.

What I'm saying is that your decision might be down to what you can get a decent installer to supply, rather than what you'd choose in an ideal world.

Some relevant threads:

https://www.automatedhome.co.uk/vbul...r-Bosch-Boiler

https://www.automatedhome.co.uk/vbul...ecommendations

https://www.automatedhome.co.uk/vbul...o-with-EvoHome

[Ubarrow]

There are a few threads covering this already (see below). Intergas is often mentioned.

I'm in the same boat, except that I have Evohome already installed.

My problem is finding an installer. The guy who installed Evohome is a Worcester guy (not surprising as we live just outside the City). I've had a couple of recommendations for other installers but I'm hesitating and am inclined to stay with the guy I know and who has been reliable - on the plumbing side, that is, we've had no need for any support for Evohome.

What I'm saying is that your decision might be down to what you can get a decent installer to supply, rather than what you'd choose in an ideal world.

Some relevant threads:

https://www.automatedhome.co.uk/vbul...r-Bosch-Boiler

https://www.automatedhome.co.uk/vbul...ecommendations

https://www.automatedhome.co.uk/vbul...o-with-EvoHome

Thanks very much for the links. When we first installed I would visit this forum a lot and spent quite a time fiddling with the system, after which I just let it do it's work! But combi boilers are a different world and it's useful to catch up.

We have a decent installer who is coming round tomorrow for a chat so I'll see what he recommends.

[G4RHL]

I replaced my boiler February 2021 with an Intergas Xtreme 36. I already had Evohome running (since December 2014). I added the Opentherm Bridge. No complaints. It seemed to take a few weeks to settle in but all works well and the Bridge does a fine job. I chose Intergas has it has consistently had good reviews. An independent site advising on heating installations came to the conclusion there were three boilers that could be recommended. Intergas was one, I think the other two were Viessmann and Ravenheat. Not sure on the last. Have a look at this site - https://www.theheatinghub.co.uk/how-we-work

I found most that I contacted for quotes, including the approved Intergas installer that I used, had little or no knowledge about the optimum settings for maximum efficiency and economy. Worcester Bosch commonly appear but service people tell me they get many call outs. One said he was guaranteed quite a few with a WB boiler and parts, plastic failing, but he gets none with an Intergas boiler.

[filbert]

How hard is it to set these things up? If my plumber isn't trained on Intergas but knows Evohome, could he & I work it out or should he stick to the stuff he knows (ie Worcester).

I'm not even sure he can source Intergas, if he isn't on their books already.

[mtmcgavock]

Personally as an installer I wouldn't have Intergas or Ravenheat.

Your issue with the big manufactures like Vaillant and Worcester want you to use their own control systems.

Baxi invested heavily in Opentherm with their own controls, so i'd look at something like the 600 or 800 series. Both good boilers and will work with Opentherm. Only downside is that they've got a low modulation range. Viessmann would be another to consider, but again i'm not overly keen.

[G4RHL]

How hard is it to set these things up? If my plumber isn't trained on Intergas but knows Evohome, could he & I work it out or should he stick to the stuff he knows (ie Worcester).

I'm not even sure he can source Intergas, if he isn't on their books already.

The fact that he knows Evohome is a blessing! As for setting up the boiler it is simple. Surely a boiler is a boiler and the basic installation is the same. The three main things, and it seems many don't seem to know this (but they do in this forum!) are the power of the boiler, the flow temperature for central heating and the mains water pressure if a combi. I can only talk with reference to Intergas.

1. Mains pressure. Mine was high, too high, well over 3 bar. The boiler likes it lower. The instructions say no higher than 3 bar. My installer did not even think of checking the mains pressure and I thought I had "normal" pressure. It was ab out 5 bar! When fitted getting hot water from the combi, particularly for showers, was a problem. Incoming pressure too great for the DHW supply from the boiler. I had a pressure reducing valve installed and reduced the pressure to around 2 bar to 2.5 bar. This produced the required balance running a shower although the thermostat knob on the showers is still turned up higher than the default setting.

2. I have not checked the default setting for the flow temperature but many have it at 75C although my installer thought 80C was OK. I told him to reduce it to 70C otherwise the boiler is not efficient and the condensing does not work properly. The sort of thing you would expect all installers to know but apparently not so. I have since experimented. I dropped it to 60C. It works fine but takes awhile for rooms to heat up. At 65C it is better but I found the most efficient for my home was 70C.

3. Power. My boiler is rated at 36kW but that is the maximum power for DMW not CH. The default setting is 19kW. That is really too high. I have reduced it to the lowest I can which is 6.4kW and it works absolutely fine. There is no need for high power for the CH. If I could reduce it further I would but this is the lowest I can get it to. I think the recent Veissmann goes down to about 3kW. Again I found installers assumed the default was where to leave it.

So, if your installer can plumb in the boiler then the settings are really something you can take control of.

I had asked for a number of quotes. Only one person knew about setting the flow temperature right and why. He was though by far the most knowledgeable and professional and my choice for the installation. He quoted for an Intergas and a Worcester Bosch. I wanted to accept his quote for the Intergas but he declined to proceed as he felt not being an approved Intergas installer he could not give me the guarantee etc. A shame as he knew what he was talking about - mostly. He could not understand why I wanted Intergas and not Worcester Bosch. I explained that my research indicated there were only a few boilers to choose from and Bosch was not one. The chap who did install my Intergas was brought up on Baxi and then Worcester Bosch. He likes Worcester Bosch for he gets lots of call outs! The parts, and there seem to be lots of them, are plastic and wear out. His preference though for quality, workmanship, no call outs and longevity is Intergas.

I have now run it for 12 months. My gas consumption is lower but all not entirely due to the boiler as I added more insulation in the loft in January 2021. Last year I used 3793.51kWhs less gas. My overall costs in 2021 were £160 down on 2020. (They won't be this year!). The whole system runs smoothly and I am sure a lot of that is the balance the Opentherm Bridge working with Evohome produces. Often if I put my hand on a radiator it is only warm and not too hot to touch as before yet the temperature of the house is nicely balanced and often I see the return temperature to the boiler in the 30s. or 40s.

[filbert]

Personally as an installer I wouldn't have Intergas or Ravenheat.

Your issue with the big manufactures like Vaillant and Worcester want you to use their own control systems.

Baxi invested heavily in Opentherm with their own controls, so i'd look at something like the 600 or 800 series. Both good boilers and will work with Opentherm. Only downside is that they've got a low modulation range. Viessmann would be another to consider, but again i'm not overly keen.

Interesting, my installer is happy with his experiences with Worcs/Bosch (and uses it in his own home) and has had problems with Baxi. He's no experience of Intergas.

What makes you say what you do about Intergas or Viessman?

[filbert]

@G4RHL - Thanks for the detailed and helpful reply. My Evohome guy came out and we had a sensible discussion about boilers, flow temperatures, reducing the power, etc. He checked the pressure without being prompted - and said (at 6 bar!) that we'll need a pressure reducer. 2.5 bar was his recommendation. He normally fits Worcester Bosch and claims not to have any reliability issues. He's looking into Intergas for me (who also happen to be local to us being near Worcester) and will find out about warranty if not done by an 'approved' installer. There's only one local installer listed on the Intergas web site and the only review I can find is *very* critical.

My guy seems to know what he's talking about and he's been reliable as a plumber as well as when he fitted the Evohome system, so I'm happy to see what he recommends.

(edit: Changed 3 bar to 2.5 following further chat re this - I think I misunderstood the discussion).

[G4RHL]

My mains pressure was about 5.5 bar. Reducing it to 3 bar was not enough. It was difficult to get the showers at a decent temperature. Around 2 to 2.5 seems best. I said nothing to my wife but upped it to 3 bar the other day. I got a comment “why does the shower seem colder?”!