Hi Guys,
Am I missing something? Why is it not standard to fill all central heating systems with anti-freeze? Also, can you put inhibitor, anti-freeze and a leak preventer all in a central heating system?
Because;
1) Why would you want to? If no part the system is allowed get below freezing, you don't need it.
2) It's expensive. Car anti-freeze is mono-ethylene glycol (usually) and it's very toxic (ensure there are no leaks in your cooling system because animals will drink any spillage in freezing weather, since it's sweet and is the only liquid available). Domestic anti-freeze should be mono-propylene glycol, which is non-toxic, but it's very expensive.
3) It goes bad; it degrades into acidic compounds when it combines with oxygen. Once acidic, it starts run-away corrosion. You have to monitor the system pH or suffer severe financial penalties. Car anti-freeze should be changed every few years.
4) You should to dispose of it as chemical waste; a bit of a problem when you need to do a drain down (I'm not sure about MPG on that score).
5) The inhibitors in it eat zinc. You certainly can't use it with galvanized pipe, I'm not sure how brass fittings would react to it; I hadn't previously thought of that. I need to research now.
The American do use it in heating systems more often (very severe winters) and their usual advice is to be very wary of the stuff or avoid it if you can. Many UK commercial systems with external pipework are trace heated, rather than use anti-freeze because it is a pain.
Insulate everything and lay off the glycol; it's a PITA.
