How to know whether my heating needs a power flush?

[JimCross]

A few weeks ago a component in my boiler died. When a plumber came out to replace it he said the system needs a power flush as the water is pretty black. He said the state of the water could have caused the issue with the component (a sensor IIRC), and may cause further problems.
Given that another plumber has quoted me £400 (8 radiator system), I'd like to make sure I'm not having it done without good reason. Is there any way I can tell that it needs doing?

[Ricky_M]

Do you have cold spots on the radiators? Does it take a while to heat up? Does the boiling make a sound like a boiling kettle?

If the answer to these questions is yes, you MAY need a flush.

Drain some water out of one of the radiators into a clear container. If it is black, hold a magnet up to the container and you should see the iron content of the water collect near the magnet.

Post a pic of the water sample for a better answer.

£400 is a reasonable price btw.

[JimCross]

Thanks Ricky, I'll give that a go at the weekend

[Dr Imran T]

I got my home power flushed as a safety measure as I was having a brand new boiler installed. I know it is not a cheap thing to do but it is better to get all that 'crap' out of the system otherwise it may cause damage to the new boiler?

A power flush does take quite a while to do - when you have your new boiler installed ask for the magnaclean system/device to be installed.

[Defcon5]

Where does all this gunk come from? Is central heating a sealed system like a cars coolant system?

[Pothole]

outer space. yes.

[philmots]

I'd be tempted to just use some sludge remover. I replaced a radiator and the water was fairly dirty but not that bad... There was a new boiler installed in '05 so it might of been flushed then.

I put some sludge remover in, think I used SP4 as that's what my local place stocked. Ran the heating for a day then drained the whole lot. I couldn't belive the colour of the water then, browny black.

After installing the new towel rail and re-filling the system and running the system I was amazed the difference, so so much hotter than before, less flunks etc.. And I never knew it really needed doing in the first place as there was no real issues.

This sludge remover cost about a tenner, and would be my first call before a power flush.

[Ricky_M]

Defcon5 said:

Where does all this gunk come from? Is central heating a sealed system like a cars coolant system?

Some heating systems are open to atmosphere, some are sealed.

The gunk is usually the inside of the rads breaking down, if you dip a magnet in the gunky water, it will attracts the iron to it.

That is the operating principle of a magna clean type device. I use a large magnet when I powerflush, its incredible the amount of crap it attracts.

Central Heating Inhibitor is designed to stop corrosion, but for many reasons isn't always present, usually because plumbers don't add it when they do maintenance.

[TVR keith]

Magna clean on mine. Brilliant!!

[B17NNS]

If you're remotely handy why not do it yourself.

http://www.hss.com/g/51610/Central-Heating-Flusher...

Not difficult, just takes a while to do a good job.

[Ricky_M]

B17NNS said:

If you're remotely handy why not do it yourself.

http://www.hss.com/g/51610/Central-Heating-Flusher...

Not difficult, just takes a while to do a good job.

Agreed, a little understanding of a heating system and it really is simple.

All you are basically doing is mobilizing the sludge and then purging it out with clean water.