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.
Gio
Very good - thnx!
Danz
It depends on vested interests. Those selling flushing services say it's essential. Many boiler makers won't honour a warranty on a replacement to an old system if it hasn't been done, I'm told.
My experience says a system otherwise in good condition which has always had inhibitor kept up to strength will have near zero corrosion, so flushing would not be required. But I'd say the removal of just one rad would soon tell the condition.
Of course perhaps most systems will have no history by the time it comes for boiler replacement so flushing could then just be prudent.
I have just had a filter installed, called a magnaclean this picks up iron oxide particles which is the sludge that develops in radiators, you can clean the filter and I was suprised how much of this sludge the filter picked up. The heating engineer had nothing but praise for the filter even though he admitted it would cut down on his work if all systems had them.
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.
I think DS40 is the most agressive stuff which Fernox makes, it will dissolve most things (including radiators if you're not careful).
So you inject the additive, leave for a week then just drain off? Then presumably you refill with an inhibitor?
Danz
You thoroughly rinse and flush with plain water in between.
Also, do check the actual sludge removal chemical in terms of how long it is recommended to leave it in the system. Some are OK for a week, others for hours only.
Don't expect these chemicals to perform miracles. If there is a lot of sludge, then mechanical removal is the only effective way.
Here's the Fernox info on DS40 ...
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