which gas combi boiler. Vaillant 838 or 938 boiler and why? efficiency?

[ajr183]

When I asked the Worcester guys they said worcester was the best. won the 'Which' award. The same with the Vaillant guy who said Vaillant was the best. Again won the 'Which' award. they both can NOT be the current winner... although the Vaillant guy did say he fits Worcester and other brands...

I was led to believe worcester were the market leader in recent times, and recently Vaillant have caught up and now over taken as the new number 1.. as Vaillant use metal internal components where as the Worcester only use plastic internals. and that Worcester were doing their best to catch up Vaillant however Vaillant were still the current no 1 , according to the Which magazine...

Now, until today, I thought Worcester and Vaillant were no 1 and 2 in any order. I couldn't care less which order as i was choosing between the best two. There were lots of other brands so if I choose either no 1 or 2 not knowing which is the best it would not make any difference, as especially if was to get 10 year warranty from the installation.

Now Iv come across a new brand which seems to as good or even better.. ????? Confused.

Veissmann have been around for years still family owned as well.

It's all about personal opinion, i've only been posting on the board a couple of days but i bet you've probably had people on here saying the likes of Ferrolli, Ariston, Saunier Duval, Chaffeteaux etc are all good boilers.

Do a bit of research, do Worcester or Vaillant make their own heat exchanger? Things like that. But remember that unless you're using UFH a condensing boiler will not get anywhere near the claimed efficiency.

Also no matter how good a company's reputation is you may get a dog of a boiler which was probably kicked down the production line and you'll get no end of problems with it.

 

[bernardgreen]

Be aware that how many rads you have and what size they are is pretty immaterial; it is the size of the house and the insulation you have that are the deciding factors.

The size of the radiators is material if the boiler is going to be able to operate in condensing mode, and since the difference in efficiency can be as much as 20% ( condensing 90%, non condensing due to high return temperature 70% ) then the effective temperature of the radiator has to be such that the return water temperature is low enough for the boiler to operate in condensing mode if the claims of reduced gas consumption are to be achieved.

If the effective temperature of the radiator is lowered to enable the boiler to be condensing then the size of the radiator has to be increased if the room is to receive the same amount of heat.

 

[kittedup]

It's all down to marketing.

A few years ago Vaillant and Worsc boilers were quality products that had great build quality. The modern day boilers they are producing now are poor reflections on their previous models with a lot of plastic inside and aluminium heat exchanges, however due to marketing the general public, and some gas engineers, still consider them to be the best.

So what happens is someone will ask for a quote from a heating engineer and ask for a Vaillant or Worsc. The installer that is only interested in winning that job will be happy to fit what is asked for regardless of the product. The better informed engineer, and the one that is more interested in supplying a decent boiler that will last and be trouble free, will suggest a different manufacturer which he knows is the much better product.

I would take the advice from the likes of Dan on here if I were you, the professionals that respond on this forum are among the most well informed in the industry.

Ted

 

[bernardgreen]

But remember that unless you're using UFH a condensing boiler will not get anywhere near the claimed efficiency.

Fan assisted radiators can be as effective as under floor wet heating. So can large panel radiators. When designing the size of a fan assisted radiator take care to get accurate figures for heat transfer efficiency at lower temperatures. The graph of heat transfer against water temperature is not linear and can droop at water temperatures that are below the bottom end of the graph

 

[ajr183]

Fan assisted radiators can be as effective as under floor wet heating. So can large panel radiators. When designing the size of a fan assisted radiator take care to get accurate figures for heat transfer efficiency at lower temperatures. The graph of heat transfer against water temperature is not linear and can droop at water temperatures that are below the bottom end of the graph

Bernard without seeming to be rude are you actually an installer?

Have you seen the cost of the so called 'fan assisted' radiators. I've only ever fitted them in the likes of care homes etc., never in a domestic property and you also have to take into consideration the cost of running the fan motors, though not a lot but it will negate the cost/effect of running the boiler efficiently at 56-60 deg.

As for oversizing rads to take into account lower flow temps you're talking of fitting K3's and they look horrendous. I've been doing a bit of ASHP work over the past 2yrs and because of the lower flow temp the majority of rads fitted are K3's. It's like having a chest of drawers stuck on the wall for rads, looks horrid hence why UFH is recommended for ASHP's.

 

[simond]

the professionals that respond on this forum are among the most well informed in the industry.

Ted

So, Ted, that means you must know more than all of us to make that judgement? You must have a lot of experience.

 

[bernardgreen]

Bernard without seeming to be rude are you actually an installer?

No I am not an installer. That said I designed and installed the heating and hot water system in the house we self built in 1981 A few years later we extended the house and modified the radiators to match the ( new fangled ) condensing boiler that was fitted as part of the extension . I also designed and installed the heating and hot water system in this cottage. ( boiler was installed by an RGI )

Have you seen the cost of the so called 'fan assisted' radiators.

Off the shelf packaged units are expensive, cannot disagree. In 1981 I used heat exchanger cores in custom built enclosures and did not get the expected results. The manufacturers when challenged about efficiency at low temperatures did admit that the low heat output was due to lower efficiency at lower temperatures. These low temperatures were not on the graph.

What I have seen are standard 2 panel radiators with three or four small fans ( mostly ex computor ) blowing air up into the radiator and this gives some very impressive improvements in heat transfer.

 

[Dan Robinson]

Bernard without seeming to be rude are you actually an installer?

You are already seeing our pain..... The resident Googleer-in-cheif that things his experience of 1 system design qualifies him to tell diyers to look for gas leaks with fairy liquid.


@Z. RANA Which? should be printed on absorbant paper. I would rather fit a coal fire than a Wooshitter, Vaillant are tolerable and Veissmann ridiculously over complicated and the build quality is poor. Had to rewire a 222 yesterday and thoroughly unimpressed. Setting the parameters was interesting as the boiler didn't do what it was supposed to.

Installed a 111 the other week, and whilst it did what it said on the tin, it felt like it was made if tin (and rubber hoses).

Our boiler of preference is the Intergas which are bomb proof and have also just won product of the year in the heating and ventilation awards

 

[bernardgreen]

qualifies him to tell diyers to look for gas leaks with fairy liquid.

Again this false hood you keep spouting

I said that Fairy Liquid can show where there is a leak, I did NOT advise DIYers to look for leaks

The resident Googleer-in-cheif

As I said some of my information comes from information sources that you ( and Google ) do not have access to.

And one small point about knowledge and who has it,

Are the people who designed your boiler of choice all Gas Registered Installers ?

Would they be able legally to install a boiler in the UK, even though they were involved in writing the instructions for how installers should install their boilers ?

 

[ajr183]

Our boiler of preference is the Intergas which are bomb proof and have also just won product of the year in the heating and ventilation awards ;)[/QUOTE]

Dan i've never fitted one my local parts place were having a big push on them recenty, are they any good?
If they are just hope they don't go the way another Dutch boiler company who came across the channel did about 12yrs ago.

 

[Dan Robinson]

What company is that? Atag?

Been fitting them 11 years and no problems of note. Pee all over most other brands for robustness and can do everything you can reasonably concieve of in a domestic situation. In fact, it can do more than Intergas UK realise.

 

[ajr183]

What company is that? Atag?

Been fitting them 11 years and no problems of note. Pee all over most other brands for robustness and can do everything you can reasonably concieve of in a domestic situation. In fact, it can do more than Intergas UK realise.

Buderus, just had a look on IG's website, got the look of a Keston on the inside

 

[Dan Robinson]

got the look of a Keston on the inside

And you think rubber hoses are a good thing?


You shoulda gone to specsavers

 

[ajr183]

And you think rubber hoses are a good thing?


You shoulda gone to specsavers

It's that big plastic tube going through the boiler, reminds me too much of a keston, sends shivers down my spine!!

What company is that? Atag?

Been fitting them 11 years and no problems of note. Pee all over most other brands for robustness and can do everything you can reasonably concieve of in a domestic situation. In fact, it can do more than Intergas UK realise.

A bit of forward think tbh, no divertor valve and only 1 heat exchanger, what's their customer service like?

 

[Dan Robinson]

Very good in my experience. Next day warranty calls.