Further on boiler choices -Viessman?

[David WE Roberts]

We were planning on installing Vaillant but we may have to change plumbers as our first choice isn't well at the moment.

Next choice plumber recommended by the builders in a Viessman installer and only deals in these. Which? only seems to recommend Vaillant and Worcester Bosch.

Plus points:

5 year warranty against 2 year on the others 10 year warranty on heat exchanger if installed by agent. CH will go down to 7.9/8 kW

Minus points: Some bad reviews around 2008 (from quick Google) Not as relaible as Vaillant/Worcester Bosch according to Which? Lower than usual hot water flow 35kW does 14 or 14.3l/min compared to

15.2l/min for the 37kW Vaillants

Pricing seems similar.

So any recommendations? Don't want to be forced to take an inferior boiler just because the plumber is an agent.

The simple specs gleaned from the Which? site seem to suggest that the Viessman may be a more efficient CH boiler, but the main use will be for running one or two showers all year round, so the peak flow rate may be the killer. Should make no difference for one shower, but could be crucial if running two together.

Which brings me to wonder if the WB38kW is a better bet than the Vaillant

37kW as it modulates lower and has the same maximum flow rate.

Ah, choices. Get well soon, #1 plumber!

Cheers

Dave R

[Rob Miller]

[gremlin_95]

I believe they are good boilers but parts are expensive! You could get 5 year warranty on the Vaillant if installed by a Vaillant accredited installer I think.

The Vaillant Ecotec 837 combi boiler will modulate down to 6.4kw* compared to 9.4kw on the Worcester. I also find the Vaillant boilers to be easier to work on and more robust overall.

*The figures on the website haven't been updated for the newer Ecotec range. See brochure.

[rbel]

I was given a 7 year parts and labour warranty on a Worcester Bosch

30CDi by a WB accredited installer last month.

-- rbel

[David WE Roberts]

O.K. - thanks for the responses so far. Nobody has yet fessed up to having a Viessman or installing one. Vaillant still seems to be getting the most recommendations.

[Tim Lamb]

In message , David WE Roberts writes

I had one installed about 2 years ago. It is currently only looking after an underfloor heating circuit so I'm not able to comment on DHW performance. Only 25kW so smaller than your needs.

The installer made a hash of fitting so it is not a good idea to stand underneath the flue when it fires up:-(

regards

>

[Dave Plowman (News)]

I have one, but it's not a combi. I self installed it and had some teething problems due to the instructions not being the best - I added the weather compensation pack and a remote programmer both of which requires software alteration. Their tech department was very helpful and sent out an engineer free of charge. Who knew about the same as me about the software. ;-)

Their tech guy eventually took me through it step by step over the phone. All I can say about it - since other than that it's been fine - is it looks very well made and should be easy to repair if and when needed.

I'd hope their current products would have more accessible software - perhaps PC controlled.

[Jonathan]

[e-mail]...

I have three Viessman boilers (2 in holiday lets). They are all different models. They have been installed for four years and have given no problems, except for 1 circuit board, which was quickly replaced by them under warranty. I do get them serviced once a year. Not enough for a statistical sample but I don't feel I want to get rid of them. The ones in the lets are combis and do drive one shower over the bath but I have had no complaints about it. The water seems hot enough when I use it to clean the bath.

Jonathan

[gremlin_95]

FWIW, we own a Vaillant with weather compensation but have only had it for about 4 years so it's too early to comment on reliability, a relative has had an older Vaillant Ecomax which is 8 years old now and hasn't given any trouble. My aunt has had a Viessman combi installed for about 2-3 years and this too has been reliable. I don't think you could go far wrong with either tbh.

[David WE Roberts]

Thanks for the further responses - only remaining question is the slightly reduced flow through the DHW compared to the norm.

14.3 lpm compared to 15.2 lpm doesn't seem a massive amount but if you can only just get away with the 15.2 lpm then this could be the straw that breaks etc.

As a matter of interest why do nearly all the mid range combis have a maximum flow rate of 15.2 lpm? Something to do with size of heat exchangers, 15mm piping, or similar? You would think they would all have minor variations.

Cheers

Dave R

[Dave Plowman (News)]

Are you certain they're all measured in the same way?

[David WE Roberts]

No idea - but still, why do they mainly seem to be the same value?

[Dave Plowman (News)]

Assuming the boilers are the same size, I doubt there'd be much to pick and choose between the flow rates at a given temp. Since they are all pretty close efficiency wise. Which is why I wonder if they're measured in a different way.

[geoff]

In message , David WE Roberts writes

Very important consideration, don't underestimate it

I'll wait and see what other people say about the other points before making further comments

[geoff]

I shall save that little gem for later ...