New boiler sizing

WIAWSNB

https://forums.moneysavingexpert.com/discussion/comment/81970447#Comment_81970447

WB appears to use their own control protocol, so it makes complete sense to use the correct WM stuff. It'll get max efficiency out of the boiler.

32kW is absolutely plenty for your situation.

How much is WB quoting? Have you tried Boxt and others? Even your friendly local GS? (although must be WB approved to get max warranty).

shiraz99

https://forums.moneysavingexpert.com/discussion/comment/81970535#Comment_81970535

For the 32kW WB are quoting around £3250 which included their Easy Control and all the usual bits, filter etc. BOXT and the like are a little more expensive and don't include the controls other that offering a Hive Mini instead. As mentioned my other option would likely be a Vaillant Ecotec Plus 32kW which is roughly around the same spec and price, maybe a tad cheaper in some places. I'm in the process of contacting some local firms but in my recent experience they don't tend to come close in terms of price.

FreeBear

As mentioned my other option would likely be a Vaillant Ecotec Plus 32kW

I think Vaillant uses eBUS which is another proprietary version of OpenTherm and EMS. So if you want to make the most of the Ecotec features, you'd want to pair it with Vaillant's controls.

The Ecotec also has a modulation range of 1:9 meaning minimum output is going to be somewhere between 3.5kW and 3.9kW depending on flow/return temperatures. So your chance of short cycling is going to be higher.

Short cycling (where the boiler shuts down and fires up again in a short period of time) is detrimental to efficiency and long term reliability.

shiraz99

https://forums.moneysavingexpert.com/discussion/comment/81970588#Comment_81970588

TBH, I'm not a big fan of using third party controls and would always look at getting the manufacturer's controls to make the most of their boiler. I'm looking at the new Ecotec Plus 832 which has a modulation range of 1:10 but I get your point that the WB would be better for modulation.

WIAWSNB

The latest Hives have Opentherm too, I understand, but that still rules out use with the WB who have their own bonkers system.

Seriously, we are in the realms of Betamax and all that barlocks.

shiraz99

On a side note, it has been noted that there is no visible earth bonding at the gas meter. Will a gas engineer refuse an installation if they can't see the bonding or will they just note it on the gas safety certificate. This seems to have been the case with this older boiler.

Edit: That said I've just noticed a card attached to the incoming gas meter to say that the pipe is PE, so maybe bonding isn't required.

FreeBear

Not mandatory for PE gas pipe, but it may be needed if you have a long run of copper outside leading to the gas meter.

Although I have a PE gas pipe feeding the meter, there is some 8m of copper running close to the ground before it enters the house. All copper pipes leading to the boiler have earth bonding - This was added after the fitter had signed off on the boiler installation (and claimed it was in place on the CP12).

shiraz99

https://forums.moneysavingexpert.com/discussion/comment/81970661#Comment_81970661

Isn't that the case with most manufacturers though? I thought only Ideal and Baxi fully use Opentherm.

The more I've looked at the WB smart controls the more I'm seeing just how awkward and a rip off it is. For a start their EasyControl is wired so if you want to have it wireless you have to purchase the optional RF card, and then it's also mains powered so you can't just put it anywhere you like and as it's also not freestanding if you don't want to use it on a wall you then have to buy the optional stand which you also have to be near a plug to use. You're dead on the mark with that Betamax reference.

WIAWSNB

I'm not having a go at WB, but at them all. It is unconscionable that there isn't a single industry standard, given how important energy efficiency is. When companies like Boxt and BG and all of them, frankly, sell - and suggest - controls that do not get the best out of a particular boiler, it's bonkers.

I've seen - set up - the controller for the WB 4000 model, and I thought it unimpressive. IF it has the option for Smart control via App, and I don't know if it does, then it should be fine. Without it, it feels like a basic, plasticky, unattractive unit that is less than intuitive - tho' workoutable - to set up and use.

FreeBear

I thought only Ideal and Baxi fully use Opentherm.

Quite a few manufacturers use OpenTherm. Intergas, Viessmann, Navien, and many others. Had hoped OpenTherm maintained a full list, but they don't.. There is an open source OT gateway that has many more boilers listed, but again, it is incomplete → https://otgw.tclcode.com/matrix.cgi#boilers

The only reliable way to find out if a boiler is OT compatible is to go digging in to the installation manual. But even if it has an OT interface, it may not support all the OT commands. Should still be enough to cover the basics.

As mentioned earlier, I have a Viessmann 050 hooked up to an ESP32 running ESPHome for the low level control and Home Assistant providing the higher level functions. The latter includes setting of target & flow temperatures, on/off times, and logging of data. Main user interface is via a wall mounted 4" display with an option to use an app. Can also select any one of a number of temperature sensors dotted around the house (including a couple of battery powered wireless devices).

I could have gone for a WB boiler and used EMS-ESP for the interface, but I prefer to use a well documented protocol.

The use of ESP and Home Assistant (other projects available) is not for everyone and does require a bit of tinkering (OK, a lot) to get running. Once set up though, it is very easy to tune the heating system to maximise efficiency.