# Boiler Kettling - General Tips



## fossyant (14 Dec 2022)

Thought I'd start a thread for people with boiler kettling and various bangs. The chemicals do work !

Ours started getting a bit noisy in early autumn - hadn't really noticed until we've stitched the heating on. The system has had inhibitor and anti-noise fluids in the past, but not for a while.

Water was inky black though !

Dropped some additional anti-noise fluid in the header tank and sludge clearer. Let that run for a couple of weeks.

Then drained down the system - left the ball cock open for the header tank as didn't want to bring in air. Hose to drain point of kitchen radiator, drained into sink (enough pressure to push the water up 4 feet into the sink). Drained until water ran clear, ran heating pump, then drained again. Repeated over a few hours (letting water circulate in between opening the drain).

Ordered some trade inhibitor (5 litres for £40 and some boiler silencer). Popped in a litre of boiler silencer into the header tank and 2.5 litres of the inhibitor in. This was more than recommended inhibitor, but it does no harm. Drained down a few litres of water from the drain point.

Left it running and over about a week the kettling has stopped.

Was only doing it when the heat exchanger got hot, so quiet as a mouse for a couple of minutes, then started "fizzing". It would continue "fizzing" when the gas shut down, until the heat exchanger cooled.

So, if your boiler is making noises, check your water, then add inhibitor and boiler silencer.


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## Pat "5mph" (14 Dec 2022)

Or get your boiler serviced every summer by a lovely young man that checks for those things


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## Petrichorwheels (14 Dec 2022)

Pat 5mph said:


> Or get your boiler serviced every summer by a lovely young man that checks for those things



sounds like he had a close escape - trust he managed to get out the door with all his tools.


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## Pat "5mph" (14 Dec 2022)

Petrichorwheels said:


> sounds like he had a close escape - trust he managed to get out the door with all his tools.


He's coming back to fit a new cooker ...


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## Petrichorwheels (14 Dec 2022)

Pat 5mph said:


> He's coming back to fit a new cooker ...



the british gas man who serviced mine once was crap.
Pronounced it fine - couple of weeks later a big problem announced itself that was caused by something he should have spotted/remedied.
Called them back and a curious youngish woman turned up, quickly sorted the thing he had missed, and started commenting on my supposedly fetching cycling legs and thighs.
I cancelled the maintenance contract soon afterwards - too much excitement.


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## neil_merseyside (14 Dec 2022)

The professional plumbers using the merchants I worked at, bunged in Fernox descaler (without any anti kettle) and when punter said system was silent they went back and drained down and re-inhibited. However the chancer plumbers I used to know bunged fairy liquid in the system on the theory the water would foam and be slightly less noisy.


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## gbb (14 Dec 2022)

Petrichorwheels said:


> the british gas man who serviced mine once was crap.
> Pronounced it fine - couple of weeks later a big problem announced itself that was caused by something he should have spotted/remedied.
> Called them back and a curious youngish woman turned up, quickly sorted the thing he had missed, and started commenting on my supposedly fetching cycling legs and thighs.
> I cancelled the maintenance contract soon afterwards - too much excitement.



It does happen. My son works for them, he will say he occasionally finds fault with the previous guys work. But its inevitable, they have literally thousands of engineers, take any profession, any company, any situation, within it, there are some good, bad and mediocre. Doesn't matter what profession, its human nature unfortunately.


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## swee'pea99 (15 Dec 2022)

fossyant said:


> Thought I'd start a thread for people with boiler kettling and various bangs. The chemicals do work !
> 
> Ours started getting a bit noisy in early autumn - hadn't really noticed until we've stitched the heating on. The system has had inhibitor and anti-noise fluids in the past, but not for a while.
> 
> ...



Thanks for that - really helpful. I thought old boilers were just noisy! 

I did actually add some inhibitor to our system recently, after having to drain the whole system to fix a puncture - don't ask - and it all went very smoothly. This stuff:







I was interested by your boiler noise stuff, so I searched on screwfix where I bought the other stuff, and found this:






...which looks like the kind of thing. But how do you actually get it into the system? The other one had a kind of tube/adaptor thing that screwed on where the mains feeds the system, but I can't see how you'd actually get a liquid like that into the system.  Your advice much appreciated.


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## CXRAndy (15 Dec 2022)

swee'pea99 said:


> Thanks for that - really helpful. I thought old boilers were just noisy!
> 
> I did actually add some inhibitor to our system recently, after having to drain the whole system to fix a puncture - don't ask - and it all went very smoothly. This stuff:
> 
> ...



Drain down an upstairs radiator, either access the bleed screw or undo one of the pipe fittings. You will need some sort of tube


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## fossyant (16 Dec 2022)

As what CXR Andy said. If you've a combi system, or one that doesn't have a header tank, shut off both valves to the radiator and drain down -you may have to undo the pipework at the valve and catch the water in a container. You can get a funnel for about £20. You take off one end cap at the top of the radiator, attach funnel, and pour in.

It's easy with an open system, but you do need to draw some water out at the bottom of the system to pull in the chemicals, although they will be diluted somewhat if added to a full header tank, but will be drawn in over a number of weeks.


It can take upto 6 weeks for the boiler to be silenced, although it's usually been within a few days. 

I got 5l for less than £30 of inhibitor, and popped in half. Inhibitor and silencer both reduce boiler noise. The inhibitor can reduce the 'fizzing' as this can be down to hydrogen in the water, hence putting in a big dose. It's much cheaper than even screw fix prices.

https://trade-chem.co.uk/heating-system-additives/c100-central-heating-inhibitor/


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## Hicky (16 Dec 2022)

The last time I had a plumber in our house to fit a rad and sort a union joint had to return three times with multiple calls to the office....many more my way as I refused to pay until I was satisfied. Eventually a few pics of the "work" was sent along with the original request.
An apology followed and the cost of works discounted. There's some awful tradesmen about....some.


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## swee'pea99 (16 Dec 2022)

fossyant said:


> You can get a funnel for about £20. You take off one end cap at the top of the radiator, attach funnel, and pour in.



Twenty _pinds_? For a _funnel_? 






Um...seriously though...having recently drained the entire system, I now know how easy it is to empty the rad in the hall, via the special draining valve thingy...so it strikes me that would be a winner if I could make the fill work (for any of the others I would have to disconnect the pipe, which I could, but I'd rather avoid if possible). 

It's about the most basic radiator you can buy - one of these:






The top ends, where I guess the boiler-magic fluid would have to go in, look like this and this:











Would this work with this presumably gold plated funnel of which you speak? Would I need a special tool to remove something, and if so, what? Many thanks for all help and advice.


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## fossyant (16 Dec 2022)

Your drain is for the system, not the radiator as you need to drain the radiator, and that valve is below the rad valves. You may have to disconnect the pipe ! I don't think the funnel will work with those over painted top caps. You may get a pipe into the rad bleed valve if you unscrew the bleed valve (one you've drained the water).


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## swee'pea99 (16 Dec 2022)

Again, many thanks. Right, first off, painted caps, no problem - I did it meself, and it's just one thin layer. The square still turns, the radiator still bleeds. 

When you say 


fossyant said:


> You may get a pipe into the rad bleed valve if you unscrew the bleed valve (one you've drained the water).


...does that mean that if I just keep unscrewing I'll eventually end up with a hole, into which I can fit a tube+funnel? 

As for the valves, ok, well I'm looking at this:






...and I'm thinking, if I turn off the water at the bottom left...






...then connect a hosepipe, out thru' the front door, from here, bottom right...






...then open a bleed valve, all the water in the radiator should gurgle out the front door, leaving an empty radiator to fill with magic fluid. (Via the 'bleed valve hole'?)

Or am I missing something? 

Thanks again. Really appreciate your help.


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## fossyant (16 Dec 2022)

You'll likely lose fluid from the heating circuit doing that as it will come up the pipe under pressure. Lock off both valves at the bottom, this then isolates the radiator, then undo the coupling to the pipe at the radiator (the silver bit at the valve - ignore the drain). Once drained, do it up tight again before moving on. If the top caps still move, once 'emptied', unscrew one (probably the one without the air bleed valve (then you can pour in the inhibitor/anti kettle). Tighten back up, open the radiator valves, and bleed air from the radiator.

A tube and funel will be cheaper than the magic adapter.

This video is how to do it.

https://www.google.com/search?clien...#fpstate=ive&vld=cid:97bca9a2,vid:llgJKzmLOLE


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## ClichéGuevara (16 Dec 2022)

If you're draining through the valve at the bottom of the system, you could just disconnect the radiator valve from the pipework, and pour the inhibitor straight in to the pipe rather than faffing with the smaller opening at the top of the radiator.


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## GuyBoden (17 Dec 2022)

ClichéGuevara said:


> If you're draining through the valve at the bottom of the system, you could just disconnect the radiator valve from the pipework, and pour the inhibitor straight in to the pipe rather than faffing with the smaller opening at the top of the radiator.



Yes, that similar to how I add the inhibitor, I put a hose pipe on the drain valve down stairs, then open the bleeder valve from the highest radiator up stairs, (truthfully I'd usually then drain the whole system). Remove enough water, then close the drain valve on the downstairs rad. Then remove the whole bleed valve from the upstairs rad and pour inhibitor into the rad with a funnel/pipe.


Bleed valve below:


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## gbb (17 Dec 2022)

A but off topic but just remembered while I was reading this...my son visited 40 homes in one shift, the vast majority with breakdowns due to condensate pipes frozen. I think one of his busiest days in years, no surprise given the temps.


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## Hicky (19 Dec 2022)

Yep, idiot of a tenant rang me Saturday morning with a frozen condensing pipe.
I asked if she’d read the UU email link I sent her…”yeah seen that and wondered what it was”. Open it and watch the vid my dear. Ring me back if you have any further issues. Ps the boiler was serviced 10 days earlier 🙄


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## gbb (29 Dec 2022)

Boiler Kettling, just asked my son, gas engineer, classic crud in the heat exchanger, be it scale (unlikely in his opinion, we live in a hard water area abandoned he's rarely seen scale cause that much of a problem).l, ot more likely a dirty system, sludge and debris from rads etc would be a far more likely reason.


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## fossyant (29 Dec 2022)

gbb said:


> Boiler Kettling, just asked my son, gas engineer, classic crud in the heat exchanger, be it scale (unlikely in his opinion, we live in a hard water area abandoned he's rarely seen scale cause that much of a problem).l, ot more likely a dirty system, sludge and debris from rads etc would be a far more likely reason.



Exactly, mine needed a good clean out, and new chemicals - it is a 27 year old boiler.


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