Best boiler for hot water flow rate with 20 l/m cold water s

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Sadly vaillant are a poor show now and hence why I don't fit them anymore.
With combi boilers it comes down to incoming flow rate, you can get the highest rated boiler but won't make a difference on the hot if you have poor flow rate.

Has the incoming main been replaced with mdpe 25mm or above?

I've fitted a wb 32cdi compact in my house with 20lpm on cold and only achieve 9-10lpm on hot with a 35c temp rise.

In your case I'd be looking at an unvented cylinder setup otherwise I think you'll be disappointed.

If you do go unvented make sure you get a g3 registered installer to have a look to see if it's suitable first and get them to get your mains pressure properly.
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If its just a better shower you're after then why not add a small unvented cylinder just for the shower. Can have it heated by the current combi you have which would mean you wouldn't need the gas pipe renewed.

All depending on space and age of current boiler obviously.


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