expansion chamber size?

26 Feb 2007
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United Kingdom
im installing an unvented heating system but am unsure of the size of the expansion chamber on the heating side i should use...is there a simple system of working this out? i know i have got to work out the total pipe length & size & the size of the radiators etc...but if someone could tell me a simple system to work it out that would be helpful..thanks
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you have to work out the system volume

BTW you can't oversize a ex v it just costs more what do the boiler mi's say about precharge ;)
it says i have to work out the system volume then add 90 litres & the expansion size is 4% of the total volume....just how do i work out the volume?
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ok you need to calc the system volume first it don't have to be spot on and allow for extra rads in the future

go over rarther than under

you can't oversize

as my old man used to say

your better looking at it than for it ;)

you can also alter the precharge to accomadate extra

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