Standard hot water cylinder capacities?

[Rex Arn]

I am in the UK.

I am trying to calculate the capacity of my hot water cylinder.

It is between 22 and 24 inches in diameter and has foam insulation on it to the depth of something like 2/4 inch. It stands about 76cm tall (sorry about the change of units) if I take a height reading to about half way up the curved dome-like part at the top.

Sometimes when I remeasure it I get slightly different dimansions.

Using basic geomery I get very approx figures of 120 litres to 210 litres.

Wow! That is a huge variation!

Maybe I can approach this from anothe rpoint of view and ask what the standard capacities are for hot water cylinders?

[Phil Anthropist]

I can't help with the geometry, I must have been off sick the day they did that.

My Fortic F3 foam lagged tank is as follows:

Total height: 1200mm (800mm for the hot tank, 400mm for the cold) Diameter: 450mm (actual copper tank, not including foam insulation) Hot tank capacity: 110 litres Cold tank capacity: 40 litres

Therefore my 800mm high by 450mm diameter hot tank holds about 110 litres.

[Bob Mannix]

Hmmmm. Can't measure and can't figure - should these people be doing DIY ;o)

Assuming the OP's tank is 500mm diameter (20" without foam) and the height to the top of the cyclindrical bit is 750mm then the cylindrical bit will have an aproximate capacity of

3.142 x 0.250 x 0.250 x 0.750 m^3

which is about 0.147 m^3, or 147 litres

Add a bit on for the dome and you could probably call it a round 150 litre tank (which is, at least, between 120 and 210 :o) ). The dome is probably a bit more and the cylindrical bit a bit less as the bases are generally dished upwards but it would be near enough.

The second posters figures are low because (a) the Fortic construction hides the domed bit at the top of the hot cylinder - I would have made it about

120l and (b) the cold tank doesn't fill to the top.

[The Medway Handyman]

This one

is

117 litres.

[Andy Wade]

There's a summary of the BS sizes on this page:

[CWatters]

That's because the volume is proportional to the radius squared. Any error in measuring the diameter of the tank is multiplied up. You need to measure it more accurately. The diameter you mention varies from 18" (=22-4) to 22" (=24-2) so that the area is anywhere from 254 to 379 square inches

[Sorcerer]

| >> I am trying to calculate the capacity of my hot water cylinder. | >>

| >> It is between 22 and 24 inches in diameter and has foam insulation on it | >> to the depth of something like 2/4 inch. It stands about 76cm tall | >> (sorry about the change of units) if I take a height reading to about | >> half way up the curved dome-like part at the top. | >>

| >> Sometimes when I remeasure it I get slightly different dimansions. | >>

| >> Using basic geomery I get very approx figures of 120 litres to 210 | >> litres. | >>

| >> Wow! That is a huge variation! | >>

| >> Maybe I can approach this from anothe rpoint of view and ask what the | >> standard capacities are for hot water cylinders? | >

| > I can't help with the geometry, I must have been off sick the day they did | > that. | >

| > My Fortic F3 foam lagged tank is as follows: | >

| > Total height: 1200mm (800mm for the hot tank, 400mm for the cold) | > Diameter: 450mm (actual copper tank, not including foam insulation) | > Hot tank capacity: 110 litres | > Cold tank capacity: 40 litres | >

| > Therefore my 800mm high by 450mm diameter hot tank holds about 110 litres. | >

| | | Hmmmm. Can't measure and can't figure - should these people be doing DIY ;o) | | Assuming the OP's tank is 500mm diameter (20" without foam) and the height | to the top of the cyclindrical bit is 750mm then the cylindrical bit

A cylindrical bit will make a round hole in his tank

should these people be doing DIY ;o)

Androcles.

will | have an aproximate capacity of | | 3.142 x 0.250 x 0.250 x 0.750 m^3 | | which is about 0.147 m^3, or 147 litres | | Add a bit on for the dome and you could probably call it a round 150 litre | tank (which is, at least, between 120 and 210 :o) ). The dome is probably a | bit more and the cylindrical bit a bit less as the bases are generally | dished upwards but it would be near enough. | | | The second posters figures are low because (a) the Fortic construction hides | the domed bit at the top of the hot cylinder - I would have made it about | 120l and (b) the cold tank doesn't fill to the top. | | | -- | Bob Mannix | (anti-spam is as easy as 1-2-3 - not) | |