Combi boiler hot water output

[fruitcake]

Was hoping someone could give me some advice regarding the dhw output from a combi boiler.

Have been looking at a few boilers and want something that will give me a decent pressure for a shower. Will there be much noticeable difference between say 12.1 litres/min and 13.5 litres/min? The mains cold water pressure is very good as the supply pipe to the house has been replaced.

Alternatively, would I be better with some kind of unvented cylinder if I want higher hot water pressure?

 

[DP]

Smallest combi will give you better hot water delivery at shower spray head than electrical shower. As the output increases, showers get better. Bigger output boiler will require more gas, which in turn may almost certainly require larger gas line meter to boiler (often neglected or 'not considered')

UV cylinders require BC notification and plans (in Scotland anyway) to be legal. But equal pressure hot and cold are a joy to have.

Do not assume very high cold incoming pressure is good for your shower. Sometimes higher pressure cold will slow the flow of hot water into shower unit. Not just my imagination- have seen it often (last one on Saturday)

 

[ChrisR]

How many baths/showers etc do you have?
Do you have a combi now? If not. then what?
Do you have space for a water store?

 

[fruitcake]

How many baths/showers etc do you have?
Do you have a combi now? If not. then what?
Do you have space for a water store?

House is a 3 bedroom semi with one bathroom.

No boiler at present, house was in a terrible mess so has been completely gutted. There had been a combi in at one stage but it had been fitted on a grant for an old person by the council so there were pipes running up and down the wall everywhere. The house is for me to move into not to sell on hence i'm looking for my best option but as i've had do do a lot of work i've still got an eye on price. Any recommendations would be very much appreciated.

There would be space under the stairs for a water store.

thanks again

 

[tonybhoy]

Was hoping someone could give me some advice regarding the dhw output from a combi boiler.

Have been looking at a few boilers and want something that will give me a decent pressure for a shower. Will there be much noticeable difference between say 12.1 litres/min and 13.5 litres/min? The mains cold water pressure is very good as the supply pipe to the house has been replaced.

Alternatively, would I be better with some kind of unvented cylinder if I want higher hot water pressure?

Pressure will be exactly the same regardless of what is installed the flow,however, will be completely different.

Best combi in terms of hot water flow on the market is around 23 l/per minute (50 something KW output) a UV cylinder will be up to 60 l/per min.

You can't touch a UV cylinder for flow rates however there is an awful lot more work involved to fit one and they can cost about the same as a top of the range combi to buy particularly if you go for a copper one.

 

[Agile]

Most people seem to find that the 22 mm water inlet controls on most unvented cylinders will not give much more than about 30 li/min before they lose most of their dynamic pressure.

Tony