How much inhibitor?

If you look at your radiator manufacturer's web site you will find volume of water in the data sheets. Sometimes it is expressed as litres per section for a given height and you have to calculate.

You can then guesstimate the volume in the pipes by taking the length and calculating the volume as cylinders - pi x radius^2 x length.

Then add on about 10 litres for boiler, cylinder etc.

You don't have to be that accurate - overdosing within reason doesn't matter. Any inhibitor is a tiny fraction of the cost of rediator replacement.

At one time it was sold in gallon or 5 litre cans. I just used one of those. Nothing has rusted out so far. ;-)

In article , al writes

Own brand stuff? The branded stuff I've seen seems packaged to suit one carton/bottle/container per 'typical' system. Unless you have a particularly large system I wouldn't expect it to be much over 100 litres, so 5 bottles should suit. If that comes to more than 15quid, buy the branded stuff as you should be able to get it for that.

Fernox MB-1 Application and Dosage The recommended ?in-use? concentration of the product is 4%. One 4 litre pack will treat an average 3 to 4 bedroom house. The product can be introduced via the feed and expansion tank or injected directly into the system via a radiator or filling loop.

Sentinel X100 Dosage: Sentinel X100 should be dosed at 1% of system volume, i.e., 1 litre per