170 litre Megaflo unvented cylinder for a 2 bed house??

A

Andagain1001

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• 24 Nov 2010

• #1

Hi
I'd really appreciate any thoughts on this...

Have a rubbish thermal store and developer is changing it to an unvented cylinder, making the boiler (Ideal Classic HE12) sealed system from open vented.

Only thing is they are proposing a Megaflo CL170, which, according to the Heatrae Sadia literature is for a 4 bedroom home-I have only 2 bedrooms so am wondering if there is anything I should be aware of aside from the fact that I will be using more gas to heat water that I don't think I will need.

For example, if/when I sell the property will I find it difficult to get an energy efficiency certificate due to my hot water tank being too big?

Or anything else, much appreciated.
Thank you

 

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studips

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• 24 Nov 2010

• #2

those babies have very good insulation and therefore low heat leakage.

plus your house is suitable for 3 or possibly 4 people? yes, 170 sounds sensible.

so this he12 does the heat and the hot water? the boiler was probably sized correctly for the property correctly in the first place, but 12kw isn't much.

 

Agile

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• 24 Nov 2010

• #3

Sounds the right boiler size to me!

Tony

 

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Tibbot

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• 24 Nov 2010

• #4

Boiler will have been sized for a thermal store. Because these act like energy batteries it enables a smaller boiler to be specified. By converting to un-vented, there is no provision for stored primary energy. There may be times the boiler is called to heat CH & HW from cold which is where it may prove a tad undersized.

 

Agile

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• 24 Nov 2010

• #5

This is a modern so well insulated two bed.

Most three bed semis are 10-12kW heat loss so that house should be less than 10 kW and so with 2 kW for hot water ( which should be times seperately when correctly set up ) then a 12 kW boiler should be fine.

Tony

 

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Tibbot

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• 24 Nov 2010

• #6

It probably is fine but I'd prefer more than 2kW for a 170 Megaflo.

 

Agile

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• 25 Nov 2010

• #7

Tibbot said:

It probably is fine but I'd prefer more than 2kW for a 170 Megaflo.

Click to expand...

So you ignore what you learnt on the Energy Efficiency course?

And the advice of the EST ?

 

Biggles..

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• 25 Nov 2010

• #8

Agile said:

Tibbot said:

It probably is fine but I'd prefer more than 2kW for a 170 Megaflo.

Click to expand...

So you ignore what you learnt on the Energy Efficiency course?

And the advice of the EST ?

Click to expand...

No, maybe he's just a realist and knows that a megaflo coil is way over 12kw to comply with the 30mins reheat time specified by the course and EST you mention, also that in reality people never grasp the idea of staggering their heating and hot water times.

The 2kw IMHO doesn't take into account modern high recovery high quantity cylinders,it was used for the old 36/18's.yes I know it was supposed to be a to up figure but with better plumbing products you see more hot water usage than ever before meaning cylinders require more than just a little topping up.