Thu Nov 08, 2018 6:11 pm #1649794
Bill McCarthy wrote:If you haven’t got one fitted, the next time you have the system drained / partially drained down, fit a Fernox magnetic filter. It has an attachment at the base of it for the addition of inhibitor / antifreeze. These treatments can then be added without further drain downs.
My filter - Fernox TF1 Omega Filter. The inhibitor is added via a pressurised disposable canister (with a fitting allowing it to be connected to the base of the filter unit).
I've got one, but that only seems to work for the addition of inhibitor, not anti-freeze. For full -11'c protection, I need to add 50l of antifreeze, albeit the reality is probably more like 20l for sensible north of england levels.
cockney steve wrote: Antifreeze will also lubricate valves, seals and pump. In the case of a power- failure , the one, isolated area of frozen installation, could potentially stop circulation in the whole system and repairing a burst pipe embedded in a concrete floor is not easy or cheap!
I guess the most vulnerable area in most modern boilers is the condenser radiator, as that is just inside the flue so close to being directly exposed to outside air temperatures, particularly if the wind is in the right direction. I suspect that isn't much difference between an internal or external boiler - but in an oil boiler there is far more water than the condenser in modern gas boilers, so should be less vulnerable to freezing.
Fortunately we don't have any concrete floors (suspended wooden floors) ... we did have a section of microbore freeze under the conservatory in Dec 2010 when we had a sustained period of sub -10'c .... but that was the same time that the water meters froze in the pavements.
I think I'd add a bit of anti-freeze to cover it for - 4'c or -5'c as a half way house.