Hi there, I am considering getting a combi boiler installed, so far have had two quotes one plumber quotes for a Viessmann 100 35kw, and the other a valliant 937 with heatstore. Can anyone pls advise me which they believe to be the better boiler? Have you had any issues with either of these? Would greatly appreciate any help
which combi boiler???
- Thread starter spain1
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I've had issues with both.
But either would be a good choice, the Vaillant is built to give an enhanced HW output, the price (and physical size) reflects this.
More important is the ability of your cold water supply to exploit the performance, and the skills of your two potential installers.
The latter is the most important, and here you, and you alone, must decide.
But either would be a good choice, the Vaillant is built to give an enhanced HW output, the price (and physical size) reflects this.
More important is the ability of your cold water supply to exploit the performance, and the skills of your two potential installers.
The latter is the most important, and here you, and you alone, must decide.
Why?
we want to get rid of our hot water tank and pipes which take up valuable room in the kitchen. We have been advised that it is the best way to go.
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a combi can usually run one hot tap well. If you are likely to have two or more people using a bath or shower and sink at the same time, you will be disappointed. It will also be slow to run a bath, but it will give a good shower unless someone else is running a tap at the same time.
Run the kitchen cold tap into a bucket, time it, and see how many litres per minute you get, and tell us. This will be the maximum flow you can get any any time, from all hot and cold taps in the house, when you get a combi. You will probably find it is less than you currently get from your bathtap, and remember that at present, your bathtap does not lose flow when someone turns on a tap or flushes a toilet.
BTW if you buy a Viessmann (I did) it is absolutely essential to get it done by one of their approved (trained) installers. That way you get their long guarantee. There is a list on the Viessmann website.
I am a householder, not a pro.
Run the kitchen cold tap into a bucket, time it, and see how many litres per minute you get, and tell us. This will be the maximum flow you can get any any time, from all hot and cold taps in the house, when you get a combi. You will probably find it is less than you currently get from your bathtap, and remember that at present, your bathtap does not lose flow when someone turns on a tap or flushes a toilet.
BTW if you buy a Viessmann (I did) it is absolutely essential to get it done by one of their approved (trained) installers. That way you get their long guarantee. There is a list on the Viessmann website.
I am a householder, not a pro.
HW tank in the kitchen? Do you live in a flat or bungalow? If so:
How big is it?
How many people live there?
How many bathrooms/showers?
Thanks, the water board checked my flow to be 20l per min, and the pressure was 4 bar. I have heard that is okay, but 25 L a min is ideal. Only occasionally would 2 people run the hot water at the same time. Currently it takes about a minute and half for hot water to run through the shower anyway, and it someone turns on tap downstairs the shower goes cold. So dont think there will be a real change to how we use currently anyway.
Combi's are great as long as the end user understands that you can't run two showers very well at all ( in fact I tell my customers on quotes that a combi is a one tap hw system - any more you need a unvented cylinder)
And the fact that the boiler breaks down you don't have any hw back up ( i.e immersion heater)
Other than that they are great - I am a Registered installer with Worcester, Vaillant and Viessmann and in my opinion the Viessmann is the better quality of the 3 - and the cheapest.....
Hope this helps!
And the fact that the boiler breaks down you don't have any hw back up ( i.e immersion heater)
Other than that they are great - I am a Registered installer with Worcester, Vaillant and Viessmann and in my opinion the Viessmann is the better quality of the 3 - and the cheapest.....
Hope this helps!
Don't forget that, if you have a combi boiler, every outlet, hot and cold, is fed from the one incoming pipe - that means the toilet(s), bath(s), shower(s), hand basin(s), washing machine, dishwasher, garden hose, kitchen sink etc.
20 l/min sounds fine, but many Dishwashers require a minimum of about 10 l/min, so you won't be left with much when it is running.
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