Flushing radiator advice

[fitzykev]

Hi has anyone every used this product or know of a better one? I have a glow worm 28c gas boiler. https://www.screwfix.com/p/sentinel-x100-rapid-dose-central-heating-scale-inhibitor-300ml/5058v

 

[Madrab]

X100 is a well used system inhibitor, it has nothing to do with flushing the rads though, that would go in after rads were flushed.

 

[fitzykev]

OK and that's an expensive job?

 

[Madrab]

Flushing the rads? Depends. if you are taking the rads off yourself and flushing them with a hose then it only costs time.

If you want them professionally powerflushed then that's a mite more expensive. Anywhere from £300 odd quid upwards, system size dependant.

 

[fitzykev]

I would do it myself. If I knew how. I only have a problem with 2 maybe 3 out of 8 radiators. Would I just do the three or do I need to do all 8 still?

 

[Madrab]

Hard to say, it all depends on how dirty the system is. If you can do it yourself then all you need to do is ensure that the radiator valves shut off properly and then drain each one, get it outside and flush it through both ways, fill it up, slosh it about, tap it at the bottom middle with a rubber mallet as that's where most of the corrosion sits etc until it runs clean.

That being said, careful as to how old and how long the radiators have been corroding for as large amounts of corrosion in them could be hiding pinholes and when thats cleaned out they could be exposed, just something to keep in mind.

 

[fitzykev]

Hiding pinholes?

 

[Gasguru]

What's the problem with the 2 or 3 rads?
I can almost guarantee it's a balancing issue and not sludge (a very rare problem).

 

[fitzykev]

The rest of the rads you can't touch there so hot but these three just get warm. And unfortunately the bedroom one makes a tapping noise when heating up.

 

[John D v2.0]

The tapping noise will be expansion of the pipes or radiator rubbing against something, you can solve that by poking around when it's heating up and finding where it is. Then put felt or old cloths or something suitable to cushion it.
Try turning off all the other radiators, now do any of the 3 get warmer?

 

[fitzykev]

I have already tried that. It sounds like it's coming from directly inside somehow

 

[John D v2.0]

It always does, resonates through like a big metal drum, could be the brackets though. Try lifting it a millimetre when it's doing it.