Hi,
So far I've got the new hot water tank and water softener in, got the chimney part orders (thanks guys) now to bring the boiler back into service.

I don't think the system has ever been flushed so I'm wondering what is the French version of Fernox for flushing the system and then an inhibitor?

Cheers

On Google it says that Fernox has offices in France.
I found references to Fernox inhibitor bidon F1.

Cheers.
I found a cleaner and inhibitor in the local DIY store but no idea if it's any good.

Theres not a market for the "désembouage" in France like there is in the UK. However Fernox is available, but I think that Sentinel is a more popular choice. Not too sure about the LM stuff as I only use the Sentinel X800 nowadays.

When you say there isn't a market for it, am I reading too much into how you've written it, is it that French don't care about it or the Brits are OTT about it and that it's not really necessary?

I think its a bit of both.

The french tend to hook up a hosepipe to the back of the boiler and let it run until clear. In the UK the use of a pump and product (such as Sentinel) is a more preferred method.

Amongst other things, its generally the mix of metals the water touches in the CH circuit that causes the build up of sludge. This can be significantly reduced by wiring up your pipework to the earth. If your boiler has a copper heat exchanger, with steel pipes feeding the aluminium radiators which have brass fittings then you will have a problem. I changed my father in laws boiler at easter and after 40 years he didn't have any sludge at all - normal - steel boiler, steel pipes and steel radiators. Even so I was still amazed that after so much time without emptying the system the water was just a dark grey.

Ooo bugger I completely forgot about the Dielectric on the boiler oh well too late now. Everything of mine is copper, except the boiler which is ferrous and as you say alu radiators, and one of the first things I did when I moved in was to add an earth bonding point.

If it's a dielectric effect how does the inhibitor work then? Ion exchange? I thought it was due to oxygen in the system?

Not too sure of the chemistry behind it all but it does work. However if you have a leak and oxygen is getting into the system then that will have to be repaired.
I don't see how its too late to earth the boiler. Take out the earth from the socket where you're boiler is plugged into and use that. It doesn't have to be a thick wire and can be done with 2.5mm2 wire

Wasn't the earth, the dielectric unions between the iron casing of the boiler to the brass and copper of the fittings. You mentioned earlier about radiators, why is it never a problem or it's standard going from copper/brass to stainless to aluminium on a radiator and it's OK, but whenever you install a hot water tank, dielectric couplings have to installed and plumbers have a fit when they see a system without.


I'm military strict about earths on everything, have 16mm to a couple of points on the system.

On hot water tanks the dielectric coupling is to prevent any premature corrosion to the cylinder. Being on a drinkable water circuit this is an obligation as any corrosion could be potentially harmful health wise. I know you don't drink hot water from the tap, but it can easily get into the cold water supply.

Its ok to go from galvanized steel to copper, but not the other way on.

Can you give me an example I'm a tad confused? What's the difference between galvanized steel to copper and copper to galvanized steel it's still the same mated surface?

Galvanized steel has a zinc coating and its the Zinc that causes the problems. However, its also about the flow of the water - you can put one before the other depending on the direction of the flow of the water.

You can take a look at this and this which may explain things better

Interesting stuff, I have an electrical background but I'd never even considered the lasagna effect mentioned in the second link