What Cylinder size?

[manisha]

Hi,

I am getting my plumbing redone and am installing a new boiler etc... We have a 3 bed house with one bathroom. We have decided to go for a system boiler with megaflow tank, but i am not sure what size tank we should go for. We are currently two adults but want to set up for the future so would like the capacity to cater for 2 adults and 2 children. At the same time i dont want a huge tank where i am always heating up unused water!

Any advice would be appreciated!

Thanks!

 

[stephenf8542]

Has your heating installer not given advise after all they'll need to size the boiler to meet demand

 

[manisha]

He has suggested we get a 24KW system boiler, we are looking at either a valiant or worchester and and advised a 210ltr tank. Just have perspective as to whether this tank size is appropriate or not so wanted a second opinion.

 

[stephenf8542]

210 is fine .A rough guide is approx 50l per person

 

[manisha]

OK, good to know. Thanks!

 

[Agile]

I think the official rule of thumb is 50 li + 50 li per person.

But its usual to not count small children as an adult as they usually have assisted baths with a small depth.

Your fear is not really grounded on facts! Most unvented cylinders lose about 1-2 kWh per day. That costs about 6-12p if heated by gas. More heat can be lost from the pipework which should always be lagged but rarely is!

So there is no disadvantage in heating more water than you may need on a daily basis as its then used up say the next day.

I have a customer called Maneesha who I take out to eat if she wears a saree.

Tony

 

[stephenf8542]

I'm saree but your going off topic

 

[izzy eckerslike]

Another factor is how hot the water is heated to, When we looked at our new hot cylinder we thought it looked rather small & were worried it might empty filling a bath & indeed it probably would take quite a lot of it .
However we soon realised that if the water is really hot then it would need a lot of cold water to make it comfortable so far less hot water is actually drawn from the tank. Our old boiler was so inificient that it needed no cold added.
At the moment we have the timer set for just 20 minutes a day & it keeps the water piping hot

 

[gas4you]

A 170 litre megaflo will do you quite nicely.

As for the need to have a 24 Kw boiler in a 3 bed house, I think it is well over the top.

I would have thought a 15 Kw or 18Kw at the most would suffice.

Does this installer know what he is talking about, or just after making more money from you by oversizing and supplying a boiler that is too big

 

[mickyg]

A 170 litre megaflo will do you quite nicely.

As for the need to have a 24 Kw boiler in a 3 bed house, I think it is well over the top.

I would have thought a 15 Kw or 18Kw at the most would suffice.

Does this installer know what he is talking about, or just after making more money from you by oversizing and supplying a boiler that is too big

Dave I was thinking the same thing, but one of the problems I find is manufacturers of system boilers only making a limited number of sizes. One of my preffered brands only sell 18 and 30kw system boilers, so they often have to be downrated on install, its an annoyance but not a major issue. On the other hand if this is not the case your absolutely right

As mentioned before heating the water to a higher temperature is a simple way of increasing the supply, however if this is going to be done its strongly recommended a TMV is installed.