how much expansion on a c/h header tank

[iwol]

hi to all could anyone tell me how much expansion is normal in the c/h header tank on an average size system(ie how far would the water rise in the header )thanks iwol

 

[REDSAW]

if the system is in good working order its a quite easy question really,


0mm

 

[sonray ltd]

0mm

try again. 0mm is wrong.

 

[iwol]

whats the answer please

 

[buffy27]

leave a fifth or the full capacity of the header for exp.
i never had any probs,by using this rule

 

[REDSAW]

100mm ish depending on system and layout/ capacity and pipe sizing.
or to be precise sonray,

V = E x C ~(1 - P1 ~ P2)

 

[iwol]

thanks guys

 

[buffy27]

100mm ish depending on system and layout/ capacity and pipe sizing.
or to be precise sonray,

V = E x C ~(1 - P1 ~ P2)

nice come back for being corrected.explain this in english please redsaw
looks very impressive.bet it would work out at pretty much a 5th of the tank capacity. cheers ,😕buf

 

[REDSAW]

on a simple factor without causing a headache.
expansion should be close to 4% of the systems water capacity at 65c.
if me memory serves well.

ok>>> volume = expansion x capacity divided by pipe capacity1 ...er foookit it hurts.

 

[buffy27]

whats the craic.
again thats super . v impressive . my problem with this formula is its not practicle at all.there would also b thermal expansion in pipe work etc . mybe i am looking into it too much,but thermal expansion would have a baring aswell.
how i remember that is that if u have a length of pipe u multiply the length when cold by the rise in water temp multiply by the coifficience of the pipe{different materials have different values. coifficience for copper is different to say gun barrel or qual pex.}
whats the 1-p1~p2 about?
with your formula am i correct in saying that u need to know volume of water in entire system.very difficult to calculate this i think.
right ,i know that if u wanted u could cylinder/pipe is piexr2x height.its changed m cubed to litres if u multiply by 1000. i m not sure , need to find some text on this one !!!!

 

[REDSAW]

er, p1 = pressure if i can remember?😕

easy way to work out actuall exp is:
mesure out estimated pipe work, each 15mm pipe per metre carries 0.145ltr. 22mm pipe = 0.320ltr. add 3m of 22mm for coil. plus 10% overall for fittings pump riser etc.
for each 600mm hight rad. add 0.10 for each column (ribs) on radiators.

add it all together and multiply by 0.04, will give you expansion to 85c heat output. which should also sujest the correct size expansion tank required. 😉
a..hem

 

[fatoftheland]

An easy rule of thumb is to allow 10% of the total water in the system. I design a heating system say at 100 litres capacity and max temp of 99degreec C (It should never get that hot) Expansion actulayy under 5 litres, Thats why I allow 10.
Obviously

An easy rule of thumb is to allow 10% of the total water in the system. I design a heating system say at 100 litres capacity and max temp of 99degreec C (It should never get that hot) Expansion actulayy under 5 litres, Thats why I allow 10.
Obviously 100 litres is a big installation but the 10% rules still applies