12 radiators - how much water?

[Nigel Molesworth]

My central heating system has 12 radiators, 15mm copper between then, and the boiler also runs the hot water.

Any guesstimates how much water is in the primary system?

[Dave Jones]

How long is a piece of string?

From the info you give got more chance of winning the lottery!

[news]

twice as long as it is from the middle to one end.

NEXT ?

[Ed Sirett]

Since you probably want to know this in the context of how much inhibitor to add.

It's about 100 lts. So one tub should do it but no harm in two.

[Nigel Molesworth]

Thanks, about what I figured. So I don't need to worry about topping up the inhibitor after losing about 5 litres from the system.

[Ed Sirett]

The rule I pretty much use is that if I hose a hose to drain then I'll add inhibitor (even if most of the water stayed in the rads) if it's only depressurizing I won't add any.

[Nigel Molesworth]

The only loss occurred while I cut the pipes to shorten them slightly, I figured it wasn't worth freezing. Naturally I found that one of them wouldn't budge at first, I was very glad of a short length of plastic pipe to make a temporary repair while I clouted the end.