Is powerflushing likely to solve my C/H problems?

[Mike Lane]

I live in a small terraced house, and the central heating system consists of just six radiators (4 upstairs and 2 down). The pipes to the radiators are 10 mm plastic microbore with valves at each end of the radiators. The boiler itself is a Worcester Greenstar Combi installed by a small local firm in

2003; I'm not sure how old the radiator system is, but I would guess about 12 years - it was already in the house when I bought it in 2000 - the pipework looks a bit amateurish to me but otherwise its been OK up till now.

My problem is that 3 of the six radiators have stopped heating properly - they only get warm to the touch even though the TRVs are fully open (they're not stuck by the way). It started last summer with the two downstairs and now recently one of the upstairs radiators has stopped working as well (this seemed to happen in a day or two). They're all slightly warmer at the top than the bottom as one might expect, but otherwise they don't seem to have any noticeable hot or cold spots.

I had someone from the firm who installed the boiler to look at it. He said that powerflushing would cost around £400 but didn't seem at all sure that it would actually work very well with microbore pipes. He suggested taking the offending radiators out off at a time and flushing them out with a hosepipe as a first step. But given that the latest radiator to fail stopped functioning quite quickly, it doesn't seem to indicate a slow build-up of sludge as he seemed to think.

Given that I'm not competent to do this or any plumbing work myself, I'm rather reluctant to get people out to fiddle around with half measures that may not solve the problem. What would the experts advise?

[R Gower]

Take the advice given by the person you called - or call a plumber. Powerflushing at £400? cowboys or what/.

[Mike Lane]

R Gower wrote on Dec 13, 2009:

[OP snipped]

What would be a reasonable price? Is it likely to work?

[John]

I would think taking them off - one at a time (or getting it done) to clean them would be a good starting point and a good thing to do anyway. Whilst off - check the flow from each radiator valve - into tray - hose or something. This will flush the pipe and let you see the flow rate.

Have you tried a heavy duty system cleaner? Then do above job.

[Phil L]

I did this last year and everything's been fine ever since. I took of each downstairs radiator (with a freind) and we took them into the back garden and flushed them through with the hosepipe, each one took about

15 mins, from coming off to going back on. Then I filled the system and allowed it to heat up to full temperature for an hour, then drained the system again, but this time, just through a drain with a hose attached, while the system was draining, I opened the filling loop so that it was filling as it emptied, so as to rinse it through, and also went around the house opening and closing valves at random, forcing the water to take different routes. When I was satisfied that it was as clear as I was going to get it, I disconnected the drain and filled the system again, but added a sludge remover and fired up the system and allowed it to circulate for 3 - 4 days, then simply drained it and refilled with clean water and inhibitor.

You say you aren't competent enough to do it, but it's just a matter of turning off the valves at each end of the radiator and removing the nuts, making sure you put your finger over the hole in the rad as you take the nut off - if you have a large cloth it would be handy to catch any drips as you get your finger in place, then it's just a matter of lifting and carrying outdoors for flushing - do it from both ends, and also, give it a shake about when half full - a radiator is nothing more than a flat metal bottle

[Cicero]

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Try shocking the system - gently. Turn off all but two of the radiators and switch the pump to highest speed. Note the number of turns required to close each valve so that the correct opening can be restored when you've finished. Check the two open radiators to see if they get hot. Repeat the process on the other radiators until you've either got all radiators hot or noted those which don't.

Remove any radiators which don't get hot and flush through with a hose pipe; turn each one upside down to help dislodge any deposits below the level of the valves. Be careful when removing radiators because any spillage will cause indelible black stains wherever it gets.

Cic.

[Mike Lane]

Phil L wrote on Dec 13, 2009:

Yes well I know it sounds a bit wimpish to say I can't do it myself, but I think in this case it's true. The radiators themselves are quite large and filled with water will weigh a lot. My background is in electronics and I have an innate fear of anything to do with pipes and water! However I take your point and I'll probably get someone in to do it for me. Thanks for the suggestion.

[Roger Mills]

No-one in his right mind would try to carry a radiator full of water - especially by just keeping the water in with your thumbs! That is a recipe for plastering your carpets with indelible black gunge - quite apart from the likely hernia. You need to drain it first!

I'm afraid that the previous poster is talking out of his nether orifice - he's obviously never tried to follow his own instructions - otherwise he would know better.

[Mike Lane]

Roger Mills wrote on Dec 13, 2009:

Yes, well these are the kind of problems I don't have the knowledge or expertise to deal with myself.

However I wish that someone could answer my original question i.e. would the so-called power-flushing process be likely to work with microbore piping, and is it a sensible solution to the problem?

[Phil L]

how would you drain a radiator full of black water, without getting any on the carpet? - plenty of people in their right mind lift rads off like this - they only hold about 10L of water.

Hang on sunbeam, are you saying I've just made it up? - I've had to take rads off in customer's houses with several different people and all of them do it this way, which is why I did mine this way - trying to get a drain attatched would result in a costly mess all over people's carpets etc, try working in the real world instead of getting your info out of a book

[Cicero]

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Yes, power flushing will work but you can save yourself a lot of money by trying the method I suggested in my earlier reply. Even if you don't want to remove the radiators you might still restore the flow sufficiently to complete the job with a good chemical flush.

Cic.

[Roger Mills]

Well, I can think of at least 3 methods - all of which I've used at various times.

1. By far the best - but it requires forward planning - is to have a drain-off lockshield valve at one end of the rad - allowing the contents of the rad to be drained into a container before disconnecting it.
2. (For vented systems) temporarily fit a suitably adapted schrader valve in place of the bleed screw, and use a car foot pump to expel the water into the header tank before disconnecting the rad. [If you had followed recent posts on the subject, you would have seen this discussed - along with pictures]
3. The default method - crack one of the connections between rad and valve and use a bent-up tinfoil chineese food container to channel the water into a bowl - having first laid copious quantities of old towels over the carpet

Well, we obviously live in parallel universes! I recently had to remove a long (1800mm) double radiator in our bedroom to decorate behind it. Even empty, it's a 2-person lift - and I drained 4 washing-up bowls of water from it (fortunately by Method 1 above, with zero spillage) before removing it. The mind boggles completely at the thought of trying to carry that down stairs full of water without spilling any!

[Dave Plowman (News)]

Only problem power flushing solves is the provider's wallet one.

[ARWadsworth]

Depending upon the size of the radiator it is possible.

Using method number 3 you place your thumb over the end of the radiator instead of draining it and your helper does the same at the other end. You then lift the radiator off the bracket and turn it upside down and walk out with it.

It is much faster than filling up washing up bowls.

Adam

[Stuart Noble]

I suppose it's a day's work. If that's all they're doing, it's going to seem expensive. If it's part of a boiler install, probably less so

[Roger Mills]

Yes, I can see that it might work for small radiators. But it does rely on having a 'helper' - which many of us *don't* have when undertaking DIY operations!

[Mike Lane]

YAPH wrote on Dec 14, 2009:

Thanks for your reply. Yes, it occurred to me that it could be the pump since the radiators seem to be failing one by one, and it happens quite quickly (the one upstairs was working fine until a week ago when it stopped getting hot). However the hot water is quite OK. Does it really use the same pump? It's a plain combi system with no separate water tank.

That does make good sense - I've already decided to get a second opinion from another plumber who seems very competent (unfortunately he's on holiday at the moment) and see what he comes up with. Presumably there are ways to test if the pump is working properly?

[Phil L]

All fine and dandy provided you own a time machine

And for unvented systems?

Yes, I can see how a chinese food container and a washing up bowl will fit under a radiator which is 150mm off the floor.

Don't you have a toilet or bath in your house then? And all my downstairs radiators are over 1800 long, and the helper in question was a 17 year old weakling

[Roger Mills]

It only takes a few minutes - and I don't pay myself £100 per hour.

You've still got the other 2 methods!

It doesn't have to fit *under* the radiator - the bit of bent foil simply has to go under the union, and the lip of the bowl has to be a bit than this so that the water will run down into it.

Yes of course - but I wouldn't fancy trying to empty a heavy radiator into either of them in a controlled manner.

[Dave]

It must be the alcoholic fog in my mind, but just how do you remove a bottom fed radiator off a wall without getting water on the carpet before you can block the openings on it?

Dave