"Gio" wrote in message ...

"Horse With No Name" wrote in message
...
Hi.
Anybody comment on the need or otherwise to "de-sludge" a heating system.
Reading around it seems it's a recommendation every ten years, but also
just read somewhere that a properly installed system should never need
flushing.
Thoughts?

Danz

I can only comment on two houses we have had in the past 35 years. Both
had their systems treated with Fernox MB1 from day 1 and touch wood we did
not have an obvious corrosion problem and as we are still in contact with
our old house purchasers we know it is still going strong with just
biannual injections of 2l into a semi drained rad. Recently when I had to
change the isolating valves on the pump because one of them developed a
leak from the valve stem and upon draining down I was surprised to note
that the CH water was not discoloured (black) I saved the water and fed
some back into the header tank. I also swapped a single rad for a double
bank unit and the old one was again clear of black corrosion. I ran a jet
hose through in case the debris was blocked somewhere but it was clear.
Oh, one house was in hard water area and the current soft water.

British gas engineers seem to inform home owners they need a pressure
flush as soon as they attend a fault (charge £450) no matter what it is
but if you limit corrosion through treatment and the system does not leak
then there should be little oxygen entering the circuit.

As I say I can only comment on my own experience and observation but I
would not have mine done as a matter of course.

I would agree, I drained down the system in my last house after 7 years with
Fernox and the water ran clear. There was a bit of black coloured water in
the bottom of the radiator I was working on, but nothing like the sludgy,
slimy jelly like substance in the system when I moved into the house.

When I moved in I found the radiators were hot at the top and sides but not
in middle. Drained down refilled etc, made a slight difference but ended up
taking each rad off and flushing with a house pipe outside. Masses of
sludge/jelly (I have been informed the jelly is copper hydroxide) was washed
out. Put all back, refilled (and Fernox) and all rads 100% superly hot.
Since been informed Fernox do some additive you can add and leave for a week
that will disolve the sludge so no need to takes rads off.