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

[steveinoz01]

Hi

I am replacing my 30w combined boiler and upgrading gas pipe to 28mm so can go for bigger output boiler. I want the best hot water flow rate available but can't find any simple comparisons.

I have filled a 10 litre watering can from the outside tap in 30 secs so have about 20 l/m cold water supply. The tap and boiler are both next to the mains as it enters the house. So seems like a reasonable way to assess incoming rate.

Its a 4 bed house with 2 bathrooms.

Any recommendations for a boiler with good hot water flow rate, preferably with a good warranty period too.

Thanks.

 

[Dan Robinson]

What does your installer recommend.?

How about the Atag Q50c


How do you know 28mm will be enough?

 

[steveinoz01]

The installer has suggested viessmann vitodens 100w 35w or vaillant ecotech 837 37w.

The installer has said that the existing 22 needs to be changed to 28mm. If you think a bigger pipe for a better boiler would be a good idea then I'm open to suggestions. Just conscious the incoming water supply limits the hot water output.

Not heard of atag q50 so will take a look. Thanks.

 

[Dan Robinson]

If you value your personal data then I would avoid Vaillant. If looking at veissmann then go for the 200 series.

I was being somewhat facetious about the Q50c. Seriously look at the Atag a325ec. 5 year warranty, built in flue heat recovery.

Gas pipe needs calculating not guessing.

 

[D_Hailsham]

I am replacing my 30w combined boiler.

I have filled a 10 litre watering can from the outside tap in 30 secs so have about 20 l/m cold water supply.

It's a 4 bed house with 2 bathrooms.

Why are you replacing the boiler? Is it because the exsting one isn't powerful enough to allow both bathrooms to be used at the same time?

If so, you would need a 50kW boiler. This will raise the temperature by 35C and give a hot flow of 10l/min to each bathroom.

An unvented cylinder would provide the same flow rate, but you would only require a ≈25kW boiler (depending on the heating requirement of your house).

 

[SilentDancer]

If you've two bathrooms and you want to make full use of the flow rate then you buy an unvented cylinder.

Worcester do a 40kw CDi combi but going down the combi route is likely to lead to dissapointment if you have two mains showers.

 

[Gasguru]

4 bed house....and you want a combi


A cylinder (perhaps unvented) and conventional boiler is the way to go. Nice immersion heater backup when the boiler packs up.

 

[transam]

u would be best advised to stay away from Vaillant

IMHO they are a dire company / mob to deal with !!!!!

 

[newbuildinstaller]

Gas pipe needs calculating not guessing.

indeed it does DanR

 

[Dan Robinson]

 

[steveinoz01]

The existing boiler is a combi so prefer to stick with combi for easier install. Only two of us in property so rarely use two hot water sources. I just want a more powerful shower.

Does Worcester 42 cdi operate off of 28mm gas pipe? If not what size does it need? The 22mm pipe is being upgraded anyway so if it needs to go bigger it can just so long as it's not silly money to cover the 10 ish metres required.

 

[Dan Robinson]

Gas pipe needs calculating not guessing.

Worcester are pants as well.

 

[Terry lambert]

I have to agree with Dan, if your going to fit a combi, the Atag would be an all round better choice.

Your installer should be able to calculate the correct gas pipe size

 

[Dean744PiN5]

Agree with ATAG a325ec if you must go for the combi route, excellent flow performance and super efficient in hot water mode, can also add a outside sensor and modulating room stat to make your system even more efficient.

Last year I replaced 3x heat exchangers on vaillants less than 5 years old @ £400 a pop not a cheap part also a very poor company to deal with.

 

[spareshunter]

Last year I replaced 3x heat exchangers on vaillants less than 5 years old

What were the reasons for replacement Dean?