Advice on combi boiler make/model

d438a1 · 18 Aug 2008

Hi there, I am currently renovating my new house and will shortly be requiring a new combi boiler when I have finished all the pipework and radiators. The house is an average 2/3 bedroom house with 6/7 radiators.

I have had one plumber who suggested going with a Worcestor Bosch Junior 24. However the most important requirement for me is a nice decent pressure on the mixer shower as I don't care for baths much.

I measured my water pressure and it came out at 15 litres a minute.

So any suggestions on boilers?

Thanks

Agile · 18 Aug 2008

If you dont know the difference between pressure and flow rate then you should take the advice of your CORGI installer.

If its an open pipe FLOW rate then its marginal.

Tony

Deleted member 105431 · 18 Aug 2008

Your best bet in my honest opinion is the Vaillant ecotec 831 or 837. Not cheap but the best on the market.

gas4you · 18 Aug 2008

Forget a 24Kw, go for at least a 30/31kw combi. Even a 37Kw will be advantageous if you really have 15 l/min flow rate.

Agile · 18 Aug 2008

dangermouse46 said:
Your best bet in my honest opinion is the Vaillant ecotec 831 or 837. Not cheap but the best on the market.

If he only has 15 litres/minute then neither of those models will reach their maximum performance!

Tony

d438a1 · 18 Aug 2008

Sorry yes I meant flow rate. I opened the kitchen tap up and filled a 15 litre bucket in 55 seconds. After reading around, I think the 30kw would be most suitable. The vaillant looks good, and agree, its not cheap! Are there any other worthy 30kw options?

Thanks

Agile · 19 Aug 2008

An open pipe flow rate is not the same as you would get through a combi boiler!

You will probably only get about 10 li/min.

There may be ways of improving your flow rate slightly but changing the incoming supply is the best. But usually costs from £600-£1200.

Of course an accumulator would give you a short duration improvement depending on the static pressure. ( Cue Simond ! )

Tony

d438a1 · 19 Aug 2008

Ok. So no other recommendations - vokera any good?

gas4you · 19 Aug 2008

Go for the 831, never had any flow problems with these on your flow rate.

Soggy_weetabix · 19 Aug 2008

gas4you said:
Forget a 24Kw, go for at least a 30/31kw combi. Even a 37Kw will be advantageous if you really have 15 l/min flow rate.

Thats the best advice on here! Put a 37 in

Putting one in this weekend (sorry Dave... its a Worcester) as the flow is 18 litres

Dave

HarrogateGas · 20 Aug 2008

Soggy_weetabix said:
gas4you said:

Forget a 24Kw, go for at least a 30/31kw combi. Even a 37Kw will be advantageous if you really have 15 l/min flow rate.

Click to expand...

Thats the best advice on here! Put a 37 in

Putting one in this weekend (sorry Dave... its a Worcester) as the flow is 18 litres

Dave

37kw combi when the gent has one bathroom and he doesnt care much for baths, has only 15lpm on the cold main. This is over specing to the extreme and wastful in energy too. I would suggest the 24kw would be fine a nd a decent shower will be had from it. Perhaps an upgrade to a 28kw may be in order for the odd time a bath is run.

Agile · 20 Aug 2008

HarrogateGas said:
37kw combi when the gent has one bathroom and he doesnt care much for baths, has only 15lpm on the cold main. This is over specing to the extreme and wastful in energy too. I would suggest the 24kw would be fine a nd a decent shower will be had from it. Perhaps an upgrade to a 28kw may be in order for the odd time a bath is run.

Overspecing on hot water doesn't matter much as it will just modulate back as required.

The problem will occur on heating because the minimum heat output of the boiler will be more than the maximum heat output of the rads even in the coldest weather. It will then inefficiently and annoyingly short cycle.

Tony

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Advice on combi boiler make/model

Deleted member 105431

Soggy_weetabix

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