Flushing pipes

[poriet]

Hi,
I have an obsolete 8mm microbore CH system with pipework badly full of that hard black stuff. Several rads have never got hot for years.
The house has a soild floor so that means that the pipework is buried in the walls and plumbers say the only solution is replacing the pipes , ha bloody ha.

Last week I took a chance and tried to clear the pipes with mains pressure. I'm firing up this w/e - wish me luck.

The reason I accessed this site was to ask if using mains pressure was a reasonable idea! It seems like I've re-invented the wheel. It's clearly a tried and tested method.
One thing I would add: many of you are professionals working in someone else's house and so this isn't an option. But what I did was to isolate each individual suspect pipe by removing the valve at one end and disconnecting the pipe from the manifold the other end. Then I blasted water from the mains straight down the pipe. We'll see.
There are 2 things more I think it valuable to mention.:
I found that I could shift more grot by forcing water down the pipe with a large ( 60mL ) plastic syringe by hand than was being dislodged by the mains! I even added some ordinary builder's sand to the water to act as an abrasive. I cant tell if it was better, but it does seem to me that some kind of abrasive material ( glass beads? ) might be an improvement on the 'power flusher with detergent' treatment currently in use.

Second: For £50 you can get a pressure washer which produces considerably more than mains pressure. I simply dont know if it's feasible to connect one to a microbore pipe ( I wouldn't try this except on an isolated pipe ) Does anyone have any bright ideas?
Regards
Bruce

 

[tonybhoy]

I would simply repalce the pipes. To h@ll with all of that b@llax

 

[poriet]

Well, well, well.
I wasn't expecting that. I get one reply and it's a silly one. Can you seriously believe that what I've done is more effort than ripping all those pipes out? Maybe we have different approaches: for you, maybe, replacing pipes in walls is easy; for me it was the other way round.

I posted this yesterday, before I fired the system up. I was anxious and not at all confident that it would have done the job and failure would have been very dissappointing. I can report now that it was a roaring success. The 2 rads in the lounge, which had never got more than lukewarm for years, were now too hot to touch. Likewise a rad in the master bedroom, formerly tepid, is now very hot.
So it seems to me that this method is highly effective and, once you get started, relatively straightforward. It also seems to me that ( well it would, wouldn't it ) it's much more effective than some of the methods being advised.
To dismantle and isolate the individual pipes may be a bit of effort, but for a DIYer, for whom time is not the limiting factor, this offers a better prospect of success that if you DONT dismantle. If you have valves and other obstructions on the pipes ( as you will if the system is virtually left intact ) then the flow will bw impeded. It may not matter if the occluded pipes aren't too bad, but surely the best prospect of success would come from the dismantling procedure I have outlined.
We may have to agree to disagree. But today I'm a very happy bunny. This awful situation has endured for years and not only is it solved, it didn't cost me anything.
Regards
Bruce

 

[simond]

I am pleased this worked for you and I think your approach was sensible, other than the sand

Your plumber was recommending the only viable commercial option, because your foor flow could have been a poorly bent pipe that no amount of pressurising could have successfully unblocked.

Those of us in the trade simply can't take these steps, because if we gave a customer an open ended quote with no guarantee of success, our paperwork would be first in the bin.

Everybody wants a fixed price, and from a contracting perspective that means we have to price an option with a known result.

As you say, as a DIYer you can take the time and the risk, in your case this was the best route. But it doesn't mean your plumber was wrong.

 

[JohnD]

you might now be in the right frame of mind to use a sediment-loosening chemical such as Sentinel X400, and fit a Magnaclean.

 

[poriet]

Hi guys
Thanks for the replies.
I do take your point about the huge difference between DIY and trade agendas. Still, for DIY, this does seem an effective soultion. And, of course, it doesn't really cost anything: just elbow grease.

You may be right about the sand. It isn't possible to tell if it was more effective than just water, but it seemed like a good idea at the time. Subsequent flushing with mains water seemed to get it all out again. It may be risky.

I feel I must reinforce the point about the syringe. I have a large plastic syringe which they use, mostly in hospitals, for taking enormous blood volumes. It's 60mL. I don't know how that translates to inches and furlongs. However, using it, I was able to shift MORE grot from the pipes than with mains pressure alone. Up to you.

Hi JohnD,
My previous experience with flushing agents was poor, but then, it would be, since nothing was actually flowing down the pipes, I guess! I'll try your Sentinel X400, but I've never heard of magnaclean. Is it an inhibitor?
Regards
Bruce

 

[JohnD]

The black sediment is an iron oxide which is attracted to a magnet.

the Magnaclean is a device which is plumbed onto a vertical pipe, the water swirls through it, and the magnet traps the black material from the water. at intervals, you close the service valves and unscrew the cap, lifting out the magnet and washing off the accumulated sediment. this takes a few minutes. it will cost you about £100 but is a fairly easy DIY plumbing job to fit. You will be amazed and delighted at how much black sludge it collects.

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