Blocked heating pipe

[Whitling2k]

Hello all!

Wonder if anyone has any tips on locating and clearing a blockage with minimum disruption.

It's a sealed heating system with about 20 rads. They all work really well - balancing can be a bit tricky but not impossible... Apart from one radiator that will not heat up!

I've tried a few things - and have come to the conclusion that I have a blockage of some sort in my supply pipe to our largest and most important radiator.

So far - I have:
1. turned nearly all other radiators off (using lockshields) and forced majority of flow through the one rad
2. removed/flushed the rad - you wouldn't want to eat your dinner off the inside, but but water can flow through quickly - so no flow problems from the rad.
3. I have replaced the lockshield and TRV

I also tried pressurising the system up to 3.5 bar and testing the flow/return pipes whilst the pipes were off - the return pipe gushed like a 3.5 bar mofo but the feed pipe barely trickled... hence my conclusion!

Accessing the pipe runs is quite difficult - however, by deduction, this part of the heating is most likely a 15mm straight T off my 22mm main supply pipes.

The T's are under laminate flooring, under a bath and boxed in plumbing... which are nailed in place with 6" ring-shank nails (by the a**e living there before us who decided at no point will anyone need to maintain anything)

The 15mm pipe work runs under said laminate, under a non-load bearing stud-wall, and then for a 9m run [under new fitted carpet ] - and 22mm T&G chipboard - nailed with 5" ring-shank nails.

This is on the 1st floor - so all said pipework is in joists between bedroom/bathroom floor and plasterboard ceiling.

The pipes cut across the joists so I would have to cut an entire 9m+ section of flooring up if I needed to access the whole pipe - however, I suspect there is little point in exposing all the pipework.

I guess I could just cut a square of plasterboard out - but other than knowing the blockage is somewhere between the T and the valve - how can I get a better idea of where to cut?

Finally, I don't want to powerflush or use any really strong chemicals - there is not enough water getting through the blockage for it to really bite and the side affects of the harsh chemical cleanser on the older part of the system would probably leave me in an even worse situation!!

Any tips/advice/suggestions?

I'm quite a competent DIYer - drained it, removed and flushed rads, installed new rads, extended the system multiple times - so happy to try most things - but this one has just beat me! (FWIW - This rad has never worked, but I had assumed it would be a sticking TRV because the flow pipe always got hot but the return didn't) - it's not my DIY that's broken it!

Ta

Whitling2k

 

[Agile]

In my view you only have two alternatives!

Expose and cut pipe!

Use acidic chemicals!

Because I dont like woodwork, I would alwys use the chemicals first.

Neat pressurised X800 would be a nervous person's start.

But I would probably use 8% HCl.

Tony

 

[freeflow]

Connect the blocked pipe to the garden hose and try running water back up the other way.

Probably best to part drain the system first and leave the drain off open when trying it.

 

[Whitling2k]

Connect the blocked pipe to the garden hose and try running water back up the other way.

Probably best to part drain the system first and leave the drain off open when trying it.

hhhhmmm yes - I could try that. quite easily because the first radiator in the system has isolating valves on T's on each leg so in theory I would only need to drain enough to isolate the two valves!

Failing that I'll try locate where it branches off the 22mm and open up the ceiling! Is there any way to identify a potential blockage before deciding where to cut or is it best to [drain] cut it and see?

 

[JBPHS]

Hi Whitling2k, is any proportion of the blocked pipework in plastic?

James.

 

[Whitling2k]

Hi Whitling2k, is any proportion of the blocked pipework in plastic?

James.

Quite probably. The rad leads are copper but they feel quite floppy - as thought there's a copper end grafted onto a plastic run. The rest of that part of the house is copper, but that's not to say this one isn't. Until I can see some of it - it may as well be drinking straw lol!

If it is plastic - I'm not sure it's barrier pipe. I removed a load suspect non-barrier as I've encountered it, but there is more.

It's grey, unbranded, with o-ring seals that work the same way as compression joints - i.e. Non-push fit.

 

[JBPHS]

Hi Whitling2k, is any proportion of the blocked pipework in plastic?

James.

Quite probably. The rad leads are copper but they feel quite floppy - as thought there's a copper end grafted onto a plastic run. The rest of that part of the house is copper, but that's not to say this one isn't. Until I can see some of it - it may as well be drinking straw lol!

If it is plastic - I'm not sure it's barrier pipe. I removed a load suspect non-barrier as I've encountered it, but there is more.

It's grey, unbranded, with o-ring seals that work the same way as compression joints - i.e. Non-push fit.

If it is plastic, it will not make much difference whether its barrier or non barrier. In the past I've ripped out plenty of barrier plastic pipe in 15mm and 22mm, yet the copper they were connected to were usually clean!

The pipe gets hot, yet there is a blockage, sounds odd with the pipe teeing off the main run so far away.

Its also interesting that you managed to pressure test the heating system to 3.5Bar, why didn't the safety valve operate???

If you would like your most important radiator to work again, I'd start thinking about how you are going to access the pipe to replacing the pipework.

James.

 

[Whitling2k]

If it is plastic, it will not make much difference whether its barrier or non barrier. In the past I've ripped out plenty of barrier plastic pipe in 15mm and 22mm, yet the copper they were connected to were usually clean!

The pipe gets hot, yet there is a blockage, sounds odd with the pipe teeing off the main run so far away.

Its also interesting that you managed to pressure test the heating system to 3.5Bar, why didn't the safety valve operate???

If you would like your most important radiator to work again, I'd start thinking about how you are going to access the pipe to replacing the pipework.

James.

It does run, but very very slowly - after about 2 hours of the heating being on, the very top of the radiator gets luke-warm but the return pipe stays cold. And the way the water gushed out of the return pipe yet trickled out of the feed pipe - depsite being under the same system pressure leads me to think there is a blockage in the feed pipe.

Both valves work fine so they are not retarding the flow - the water does flow through the radiator as proven when been flushed through.

Therefore, if the pipe wasn't blocked and a decent flow of water is getting channeled through the radiator - I would expect the return pipe to show some sign of heat.

I just can't think what else could cause that observation other than a kink in the pipe or a stuck/partially closed isolation vaslve thats hidden somewhere.

It's really unfortunate that the pipe runs 90 degrees to the joists so I can't cut one hole and then shine a torch along the gap.

I had wondered why something didn't blow at 3.5 bar - but it didn't! or if it did, I didn't notice!

I think my next step is to blast water through the wrong way (and out at the next rad!)
if that doesnt wotk, try find the T, cut that out, see if I can manually clear the blockage - failing that, lift floors in bedroom and replace the entire 9m or so run.

if that doesn't work I'm selling up lol!!

 

[Whitling2k]

Morning all!

Thought I'd post a quick update... The radiator is working fine, my entire system heats up in half the time, it's near-silent now and actually heats the house!

I crafted some copper pipe onto the end of two hose pipes with hose-clips, and then attached these both to different flow pipes, at either end of the suspected blockage, using compression fittings. I closed all other radiator TRVs and lockshields and isolated the boiler.

From the outside, I now could push and pull mains pressure water through the pipework - swapping the other end of the hoses between drain and tap to reverse the flow.

So I started with the suspect heating pipe - starting slowly with an assistant watching for leaks, I first sending pressure down one flow pipe - I got a trickle out the hose - and then it stopped. I then reversed the flow - pushing it down the other flow pipe - again, a trickle followed by nothing. I did this a few times each time a bit more water came through - until eventually, a gurgle, a splurt and OMG... about 2 minutes worth of black crud flowed out like nothing I've ever seen - it was settling to about 1" deep on the grass.

I reversed the flow another couple of times until the water came and went with no gurgles and no gunge.

After that I moved one end of the hosepipe onto a return pipe, so one on flow and one on return, and opened both valves on one radiator. I was pushing water down the return pipe and letting it return up the flow pipe for about 10 minutes - 'till the juices flowed clear'

I then systematically went around each radiator - opening both valves, going back and closing the previous radiator - giving each one and all the pipework a really good flush.

after that - I did some work replacing a broken radiator (thoroughly flushed through before being online) and then fitted my SpiroMaster MB3 on my return pipe just before the boiler, and a full-bore isolating valve to aid future maintenance.

It was at this point I realised I'd been scammed on Ebay - 5 bottles of x800 - all of them had been syringed out and filled with some cr@ppy orange stuff that had gone lumpy - some @$$wipe had sold me something what wasn't x800! luckily - I was using my new radiator as my dosing point, so managed flushed all the rogue chemical out, placed one bottle of x100 in and fired up the boiler..

A few weeping compression joints and a blocked automatic air-vent was all that stood between me and a warm heaven! All was good.

The heating warms up so quickly and quietly that I'm going to leave the x800 for a while - now I know I can easily flush my full system in a matter of hours and I have my filter in place - if things block-up again I'll flush and then use the x800.

My final task was to dose the final bottle of x100 (20 radiators - so need 2 bottles!). because I had the entire system now filled, and wasn't going to empty it any time soon, my usual trick of a funnel into a bleed-port wasn't going to cut the mustard..

Queue crazy invention time! One water filter with 1.2l reservoir, 5 flexible tap hoses - 3 isolating, a compression T- joint, 3 short lengths of copper pipe, an in-line compression joint and a 9" length of copper later... my patented (£30 worth of equipment's) DIY chemical doser!! works with the entire system under pressure, doses 1 litre at a time and does so in a matter of minutes. (see pictures!)

All good - I felt at the limits of my DIY skills at the start, once I had got into the routine was quite straight forwards and rewarding.

Just needed to be systematic and keep concentrating to not accidentally leave bleed valves open or start the boiler when still isolated etc!



MB3 in situ

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• Whitling2k
• 8 Oct 2014
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DIY Doser

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• Whitling2k
• 8 Oct 2014
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• Whitling2k
• 8 Oct 2014
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• Whitling2k
• 8 Oct 2014
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• Whitling2k
• 8 Oct 2014
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