On 20 May 2004 03:42:12 -0700, (Bloss) wrote:

I'm putting a radiator in my conservatory so I can use it on the odd
day in the winter so I'm going to add Fernox alphi11 antifreeze to the
system. How much do I need to add? They reommend a 25% mix, is there a
quick way to calculate the ammount of water in the system so I don't
have to drain the whole thing down.

Before anyone asks part of the system has stop valves so I don't have
to drain down to fit the new rad.
Thanks

The hard way. I needed to do this for a separate circuit that I
have heating my workshop.

Find the radiator types or one close to it on a radiator
manufacturer's web site. Obviously there are various types with one
or two panels. Normally the data sheets give a water capacity in
litres per section for a given height of radiator. Count the sections
on each radiator in question and multiply out.
This will be the largest amount.

For the pipework, guesstimate and treat it as a set of cylinders.
Add up the 15mm runs and the 22mm (and other sizes) in terms of length
(two legs remember). Multiply diameter by pi and by length to
determine the volume, remembering to get the decimal point in the
right place to determine litres.

The HW cylinder and boiler together you can count as 10 litres. Add
another 5 for the header tank or pressure vessel.

As a sanity check in a typical house you will be between 50 and
150litres.

Work out the Alphi-11 on that basis. It doesn't matter too much if
you go to higher concentration than 25%. I have mine at about 35%.





..andy

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