Please help choose: WB Greenstar 4000 or Vaillant ecoTec Plus 832 combis.

ThisIsWeird

Asking for a friend, who has short-listed the above two combis.

I don't know enough about them to assist much, but assume they are both well-regarded, and presumably come with solid 10-year warranties.

The WB is 30kW, and the Vaill is 32kW - not much difference.

One issue is, this friend's GS doesn't want to fit WB for some reason - he just says he 'hates' them.

They also want to fit decent Smart controls, which will use a number of Smart TRVs, so I mentioned that the type of communication protocol between the controls and the boiler could/should have a bearing on their decision - eg things like Opentherm.

Thoughts, please?

1) Choice between these two boilers, and why?

2) What control protocol does each use, and what would be the best CH control system to use?

On that last point, my friend is quite keen on Tado as it's user-friendly, reasonably priced, and has all the 'Smart' bits like TRVs. But, will Tado get the best out of these boilers?

What about Wiser, as FreeBear recommends? Will that provide everything required? Is it as nice to use?

Many thanks

FreeBear

Neither the WB or Vaillant support OpenTherm - WB is EMS, and Vaillant uses eBUS. Both propriety and closed systems (although some have reverse engineered the protocols). You won't be able to use Tado with Vaillant if you want full modulating control unless you add a VR33 module (which may invalidate the warranty). Some of the Tado kits "do" EMS, so can work with the WB, but don't quote me on that.

If you want OpenTherm, then Viessmann, Baxi, Intergas, and others would be a better choice. I would however question the need for a 30kW boiler - Few really need one so big unless it is a combi with a high DHW flow rate. For heating, much of the time it would be just ticking over and efficiency tends to drop off.

My Viessmann 050 is delivering a peak of ~9.5kW to the central heating at start up, and then drops to 3-4kW. Based on the data collected over the last month, efficiency is around 88% - Quite a bit short of the 95+% that I should be getting with a 50°C flow temperature according to Heat Geek.

One more point - Has this fiend considered a heat pump ?

With the availability of a £7500 grant, some outfits like Octopus are quoting installation costs on par to a gas boiler. A HP on the right tariff could work out quite a bit cheaper to run as well.

ThisIsWeird

Thanks a lot, FreeBear - just the sort of info I was after.
I mentioned 'Opentherm' just as an example - it doesn't really matter what protocol is used, provided the controls are available, and at a reasonable cost.
WB's EMS, and Vaillant's eBUS - do these companies provide a good range of Smart controls, including TRVs, do you know?
Or, does a system like Opentherm, EMS or whatevs actually make that much of a difference, enough to justify a tied, same-make, control system?
I haven't mentioned ASHPs, and have no idea if that's something they've considered, but will do so - and they'll be following this thread anyway
Yes, they are combis, hence the 30+kW.

ThisIsWeird

ASHP not possible as they live in a maisonette, and such ugly beasts have been outlawed in the building. And no room for a Heat Store.

So the Q is, do WB or Vaillant supply a good selection of Smart controls that'll give their potential customer what they want, what they can get from, say, Tado or Wiser? Or do normal folk still have to go 3rd-party for this? Which is, of course, completely nuts.

Or, to put it another way, just how much is lost in the efficiency stakes by not having the Opentherm/EMS/eBUS additional modulation?

This is all completely bonkers. I understand that 'Opentherm' was meant to be a control 'standard' - a bit like Betamax or a Lightning Port. Why in all that's unholy do boiler manufacturers still have three or more different protocols? Oh-no, O-T ain't good enough - let's do ours! And then not make it work.

I've just had a read of Tado's own forum, and folk on there - who really understand this stuff - are pulling their hair out at the loss of this modulation; they are looking to buy EU units, or add-on boxes from eBay, or adding relays, or weird cables! BONKERS! What's WRONG with boiler manufacturers?!

If my friend goes for, say, the WB, and then adds a Tado control system, what will they actually lose out on? A percent or two of efficiency over 4-5 months per year? £20 per annum?

Or, is it really worth sticking with WB for all the controls, Smart TRVs and everything?

SaverRate

Had a WB Greenstar 4000 with nest control in my old house and the Vaillant 832 with Vaillant controls in my new house.

In all honesty not noticed a huge difference between the two in terms of heating up times etc. I prefer the control panel on the WB and the filling loop I preferred on the WB but those are minor things. The Valliant app is better than the nest app but then its not really like for like. 

I have installed TP Link (kasa) TRV's just so I can control the temperature of the TRVs easier. Seem to be okay but obviously doesn't link to the Vaillant smart control. 

ThisIsWeird

SaverRate said:

Had a WB Greenstar 4000 with nest control in my old house and the Vaillant 832 with Vaillant controls in my new house.

In all honesty not noticed a huge difference between the two in terms of heating up times etc. I prefer the control panel on the WB and the filling loop I preferred on the WB but those are minor things. The Valliant app is better than the nest app but then its not really like for like. 

I have installed TP Link (kasa) TRV's just so I can control the temperature of the TRVs easier. Seem to be okay but obviously doesn't link to the Vaillant smart control. 

Interesting, SaverRate.
I presume the manufacturer's own dedicated system will provide the finer, modulated, control each boiler is capable of. 
I notice that WB have their own Smart TRVs - do you know if Vaillant have these? The TRVs need to be able to control the boiler so that the system is properly automatic.
It may be worth forking out the extra cost of the manufacturer's own system?
Cheers.

FreeBear

ThisIsWeird said:  just how much is lost in the efficiency stakes by not having the Opentherm/EMS/eBUS additional modulation?

This is all completely bonkers. I understand that 'Opentherm' was meant to be a control 'standard' - a bit like Betamax or a Lightning Port. Why in all that's unholy do boiler manufacturers still have three or more different protocols? Oh-no, O-T ain't good enough - let's do ours! And then not make it work.

https://www.beama.org.uk/static/7f5ebe31-04e1-470e-9befd249359959d9/15d07ed2-35d0-4c9f-90f958f81e9425f6/Salford-tests-on-load-and-weather-compensation.pdf suggests a thermostat capable of "talking" to the boiler and modulating the output could save in the region of 10%. Personally, I think that figure is a bit optimistic especially if you already run at a relatively low flow temperature. The real saving comes from not having the boiler short cycle, which reduces wear & tear as well as a small reduction in gas consumption.

Despite OpenTherm being an open "standard", through my work with assisting in the development of some control software, not all manufacturers are singing from the same sheet. The core set of commands appear to be the same, it is just some of the informational commands that are supposed to be mandatory are missing or deviate from the published specification (boiler fan speed is one that has caused issues recently). But at least much of it is freely documented unlike EMS or eBUS.

That said, there are projects out there that provide connectivity to EMS and eBUS if you want to integrate a boiler in to a smart home control system. EMS -> https://emsesp.org/ eBUS -> https://ebusd.eu/ and finally, OpenTherm -> https://github.com/FreeBear-nc/esphome-opentherm - The OT stuff has made its way in to esphome and should hit mainline shortly.

ThisIsWeird

Nice stuff, FreeBear! I didn't know you had that involvement.
I think it's absurd that a single control protocol hasn't been established - insisted on - so that the max efficiency can be brought to bear by different 3rd  party control providers. But I guess that's the point.
For a layperson like the one with this current dilemma, the choice is seemingly to go for that manufacturer's control system - assuming it has everything required, such as phone App control and TRVs - or to compromise with a non-modulating, but cheaper, 3rd-party setup. To contrive a combination is not practical.
Lawdie.

ThisIsWeird

For the WB, it appears that their 'Easy' control range is the one that'll also do Smart TRVs, phone App and all that malarkey. It also uses the EMS protocol, so should be as efficient as possible.

It does look good, tho' I don't know the cost:

https://www.worcester-bosch.co.uk/products/boiler-controls/bosch-easycontrol

FreeBear

Screwfix says £160.

Reviews, not so good.

ThisIsWeird

FreeBear said:

Screwfix says £160.

Reviews, not so good.

Thanks - that's what I heard
Anyone on here got actual experience of it?