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Anyone had a 'power flush' (central heating not menopause!!) - Piglet John??

(21 Posts)
Seeline Wed 12-Nov-14 09:01:16

Our central heating has been playing up for a couple of months. We often don't get heating downstairs and the system makes horrendous bangs and crashes.
British Gas say that it is because there is so much sludge in the system, and they can't do much more about it and recommend a power flush (£1000!!). The system already has a Magnaclean thingy on it as recommended and fitted by BG.
Has anyone had similar problems and ended up having a power flush? If so did it work? How much chaos did it cause?
Are there any other possible solutions/causes? We were wondering whether replacing some of the very old radiators might help. Not sure exactly how old they are but must be at least 30 years old.

madasamarchhare Wed 12-Nov-14 09:07:02

You probably need pigletjohns advice. We did have a power flush a couple of years ago can't remember the reason why. Took most of the day and obv had no heating or hot water but was no problem other than that. Certainly costed nothing like you've been quoted we used a local v reliable plumber and I'm sure it was less than 500 probably actually nearer 250-300. Hope that helps

Seeline Wed 12-Nov-14 09:18:44

Thanks Mad - I was wondering about the cost. We have a service agreement with BG and they said if they did the work it would be guaranteed by them, which seemed a good idea, but if the cost it so much more, it might be worth looking elsewhere!
I am hoping PigletJohn will be along soon grin

BranchingOut Wed 12-Nov-14 09:22:18

We had a powerflush done and it definitely helped to eliminate cold spots and moans/ groans in the system - a whole bucket of sludge came out as far as I can remember!

Think of it as a bit like cycling the legs of a windy baby!

cattypussclaw Wed 12-Nov-14 09:23:47

Yes, I've had two (we must be particularly mucky). It just involves draining down the system (there's a little outlet doofie somewhere on your system) so it's not messy indoors (when they did ours we just had a hosepipe running down the drive to the gutter). So no heating or hot water for a few hours but no mess. Not sure whether it clears sludge from the boiler or just the radiators (Piglet John will know) but we actually needed a new heat exchanger in the boiler as it was so gummed up. Do you have a HomeCare agreement with BG? Is the cost not covered by that? Ours was...

vinoandbrie Wed 12-Nov-14 09:25:37

We had a power flush in similar circumstances to the ones you're experiencing, ie build up of sludge in the system.

We had it done by British Gas, and it was about £800 as I recall, which made me take a sharp intake of breath. To say the least. If we'd known anyone local and reliable who'd have done it cheaper, we'd have gone with them.

On the plus side, it worked, solved the problem, and there was no mess involved, minimal disruption and it was done in a day.

Seeline Wed 12-Nov-14 09:27:23

Cattypuss - I think that is just a drain down and probably would be covered by our homecare agreement. What they area proposing is pumping water (and chemicals I think) at high pressure through the whole system. The engineer said something about having to deal with each radiator in turn and bashing it to get the muck out. It would take at least a day!!

HeyMacWey Wed 12-Nov-14 09:31:01

We had a power flush before new boiler was fitted. Certainly didn't cost what you've been quoted.
Have a magnet thing fitted to maintain.

Seeline Wed 12-Nov-14 09:37:30

We've got a magnet thingy already - had it for several years but obviously it hasn't been much good grin

specialsubject Wed 12-Nov-14 10:31:02

how often are you emptying the magnaclean?

what size are your pipes? Powerflush won't work with smaller ones.

old systems can be destroyed by a powerflush. You can do a chemical flush which goes in, is left for a few weeks and is then washed out.

£1000 is well OTT For a powerflush.

Seeline Wed 12-Nov-14 10:37:48

The magna clean is emptied once a year on the annual service , although it has been done twice in the last couple of months due to the problems.
No idea about the pipe size.
We have had a couple of chemicals put in the system, but they haven't be washed out again. Worried about the age of our system now, although the boiler itself is only 7 years old....

specialsubject Wed 12-Nov-14 10:43:16

hmm. We had a magna clean fitted when we changed our boiler, still had the old pipes and mostly old radiators. We were emptying it monthly or more for the first six months until it came away clean.

sounds like half the job or less.

Butterpuff Wed 12-Nov-14 10:47:16

A friend who is a plumber was telling us hilarious for him horror for the owners stories just this weekend about power flushes. Fine if your system is in good order, not so great if you have any weaknesses. He told stories of exploding pipes and floods in old and new houses. But he may just be a bad plumber!

TheSpottedZebra Wed 12-Nov-14 10:48:10

I'm in the same place as you, OP. We have a magnet but this year there have been loads of bangs and crashes and a few cold spots. Yet our system is 25 yrs ish old, so not sure if a power clean would just destroy it. Hmmm. .....

PigletJohn Wed 12-Nov-14 14:29:16

If you have a Magnaclean already, it is a bit unusual to be told you need a powerflush. The £1,000 might be an influencer. Did they mention a defect in design or installation of your system that causes air, or fresh water, to be drawn in?

I presume that your system has a feed and expansion tank in the loft (like an old WC cistern) and there is not a pressure gauge on the boiler.

If you want to try a DIY chemical clean, it will cost you about £30 and a couple of afternoons. You will need to find the F&E tank and the drain cock. It may do the trick but will anyway do nothing but good. Empty out the Magnaclean today, and scrape the sludge into a jamjar. This is easy if you slide the plastic sleeve off the magnet. Keep it to compare with what you get in a couple of week's time.

cressetmama Wed 12-Nov-14 15:25:31

Are you in a hard water area? It is possible to descale hot water systems using the right chemicals. Google descaler and ask your plumber about circulating it around the system to get out the gunge. Piglet John's instructions may be all you need, but I'd want someone to hold my hand!!!

Seeline Wed 12-Nov-14 17:51:56

Thanks for this everyone!
PigletJohn do you just 'unscrew' the magnaclean or do you have to shut off the water first? Ours is right next to the pump (or maybe attached to it?!) in the airing cupboard. Really don't want to flood the house on top of everything else grin

AryaUnderfoot Wed 12-Nov-14 18:24:46

We had a similar problem. Downstairs rads never got hot while the central heating and hot water were both running. The only way to get downstairs hot was to switch off hot water.

There were numerous problems including the rather old central heating (late 70s) and the fact that the central heating circuit is in 15mm pipe and the hot water is in 22.

BG said that they would no longer cover the central heating under the service agreement unless we got a power flush for about 1000. I got some advice from my dad (he worked for BG for 35 years and his colleague 'invented' power flush) and he confirmed it was probably a good idea.

In the end we got a power flush done along with a replacement boiler and mahoosive hot water cylinder for 2600. Problem solved.

AryaUnderfoot Wed 12-Nov-14 18:25:49

We didn't get the work done by BG though.

specialsubject Wed 12-Nov-14 18:29:53

the magnaclean came with instructions, I hope, and also the correct sized tool for undoing it.. You need to close the valves next to it to prevent a 'water everywhere' situation.

you'll also need to bleed it occasionally.

PigletJohn Wed 12-Nov-14 18:48:25


yes, there is a (probably silver or red-painted) valve on each of the two pipes that connect to the Magnaclean. You have to turn them both off with the small silver flat spanner, then loosen the bleed screw in the middle of the lid to check that water does not squirt out, before undoing the black cap with the big flat black spanner (you do not use the spanner when putting the cap back, just tighten it by hand). After cleaning the sediment off the plastic sleeve and reassembling, check that the bleed valve is shut before turning on the two valves, then bleed it again for any trapped air.

If you have lost the instructions, search for "magnaclean instructions" or "Adey" (the makers) and you can probably download them.

I recommend putting the spanners in a small translucent bag and hanging it on the Magnaclean, tied together with string

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