Gas Central Heating

[BJS]

What is the name of the liquid that can be added to the system to prevent clogging etc. Is this a good thing to do as I believe its quite expensive.

[ukbod2015]

Fernox

[bhg481]

I use Fernox 1B. It stops corrosion and so the need to bleed the system. My system is 30+ years old, I top up the Fernox every 7 or 8 years and I've never had to bleed the system or had any problems with it. I very strongly recommend it.

[BJS]

I forgot to mention due to a leak under my concrete base most of the pipework from boiler to the rads was changed to some sort of flexible piping. Still assume it would still worth doing.l

[bhg481]

It's the steel radiators which corrode.

[Bazile]

How do you introduce it into the central heating system?

[bhg481]

Just pour it into the header tank, usually in the loft; you might need to take a bit of water out first. As the water in the system heats and cools it expands into the header tank and contracts out again so it gets into the system fairly quickly.

[Baldric]

Depressurise the system and introduce it via an upstairs radiator is what I've done in the past

[Baldric]

Do people still have header tanks with Combi Boilers?

[bhg481]

I don't have a combi-boiler, so I wouldn't know.

[Bazile]

I've got a combi - so no tank .

Bear with me - but how do you depressurise the system .
Do you also detach the radiator / take the valve off to introduce it ?

[Baldric]

Drain some water out via bleed valve, remove large nut behind b/valve,
use funnel to get Fernox into system, replace nut and valve, repressurise system, job done!

[Bazile]

right ho

[BJS]

Thanks for all the answers much appreciated. I have a Combi and live in a bungalow so all my queries have been answered.

[BJS]

Actually after re-reading your last Baldric if I'm reading it right you say some water off thro the bleed valve and remove large nut behind it and using a funnel add the Fernox, As the bleed valve is horizontal I assume you can get a right-angled funnel or am I just a silly old fool.

[bhg481]

You can get funnels with a bendy outlet tube.

[BRIGHT SPARK]

BJ......as you live in a bungalow, the chances are, that the boiler will be the highest point in the system.Bleeding some water from a bleed valve wont do it.You may have to drain part of the system and inject the Fernox through a bleed valve nut at the top of a rad... when sufficient water has been drained off.....then re-fill.

[BJS]

One last question on this subject(I hope) is it worth draining and then flushing out the system first before applying the Fernox. Once again thanks for all the answers. What would us old fellows do without this site.

[BRIGHT SPARK]

The system may benefit from flushing...however check out the water coming out when you drain down....if its clean then dont bother.How old is the system BJ?

[BJS]

The boiler was fitted 2002 and I think Fernox has been used at least twice, the last application could have been 2008.

[BRIGHT SPARK]

If the inhibitor strength has been kept constant then flushing may not be required as a combi system is generally sealed unlike a conventional open vented system.