“Powerflushing” a CH

[Tim+]

My mother has had some combi boiler trouble recently, first a diverter valve that wasn’t switching properly when HW was called for and now a mysterious leak from somewhere internal.

According to the Scottish Gas fitters, bits were heavily sludged. As a special offer they’re offered to come back tomorrow and powerflush the system for £600 but they want a quick decision which rings alarm bells with me.

Is this a typical price for the service or are they lying swindling bastards? Is it the sort of thing than can be done by any competent heating engineer and what should one expect to pay?

Tim

[Tim+]

I?ve been searching a bit and prices seem to start around £250, but then about an extra £25 per radiator (which includes towel rails). Her system probably has about 12 radiators so maybe it?s not *that* out of order.

Tim

[Fredxx]

This is a DIY group!

You can take the radiators off yourself and flush them with a hose!

You can always find someone else cheaper who doesn't give you a deadline to accept their offer.

[John Rumm]

It sounds a bit on the high side for a 12 rad system, but not quite into the obvious rip off territory.

[tabbypurr]

I certainly wouldn't. Fit a Magnaclean, or better a Zetec. Add cleaning stu ff to the CH & replace with inhibitor, a few weeks later if it's real bad. Be prepared to clear the filter at times when it starts clogging.

Once that's done (for under £100 and provides long term debris clearan ce) then you'll know whether it actually needs a vigorous flush.

NT

[Rednadnerb]

I am also in the position of having to decide whether to get a powerflush o r take off the worst offending rads and clean them out. The worst offending rads are on the ground floor. Does anyone know whether sludge settles evenly throughout the system or doe s it tend to settle in the ground floor rads?

[Tim+]

I would do that in my own house but this is some distance away and I?m not sure I?m confident I?d know how to flush all parts of a combi boiler.

Tim

[Brian Gaff]

I'd say the latter myself. I'd not do it with the first company who came along even if they were cheap! Get some quotes. Brian

[Brian Gaff]

I'd also be very careful as it might show up lots more leaks. Also it would be good to know what sort of gunk was in the system to supposedly keep it sludge free and when it was last flushed. Some people around here have also found that even after a complete flush it has to be run for a while then redune at least once more if its heavy nasty gunge inside. I'm not up to speed with current flushing fluids etc, though.. I often wonder how many of these concoctions are based on snake oil. Brian

[David]

Reading the site in more detail, they claim that if there are difficult radiators where the sludge can't be released by vibrating or tapping with a rubber hammer, then they take the radiator off the wall and power wash it outside.

The complete process seems prone to risk if the system is badly gunged so the price might be higher to cover potential extra work.

They have to rebalance the system as well.

Full day's work if done properly.

However the actual work is pretty simple and not much different from an install or replacement of a system so the main thing is to have a trusted operator (always the tricky part).

I think the test for a badly sludged system is to feel for cold spots in the middle of the bottom of the radiators.

Cheers

Dave R

[Dave Plowman (News)]

If it is heavily sludged up, one or more rads will be blocked and not working properly. If they all still work, adding a cleaner to the water will flush it through. After doing that, use inhibitor to prevent future sludge. All easy DIY.

[Dave Plowman (News)]

You just follow the instructions on the pack. Basically add the cleaner and run the system for a while, then flush.

[Vir Campestris]

I'll go with the latter. Even if, as others have said, this doesn't seem to unreasonable a price.

British Gas told my mother in law that she needed a power flush, which she duly paid for. It made no difference. The _actual_ problem was that she had single pipe radiators - feed and return going to the same point. From the valve there's supposed to be an internal pipe going to the other end. Which had fallen off.

Andy

[John Rumm]

It does not settle evenly, but its harder to identify where it will settle. It tends to be places where there is less flow velocity, but can equally be where there are branches or restrictions, or more "difficult" escape routes for the water. Those places may be downstairs, but could equally be elsewhere.

[rick]

Recently flushed my sons system ..... put in a cleansing solution, run system for a week ... Opened all lockshield valves .. and thermostatic valves to max ..... got system nice and hot and drained it ... them connected up a hose run it until l all drain points run clear.

Filled and emptied a couple of time.

Then filled and added inhibitor.

May not have got rid of all .... but got rid of a lot.