# All sludged up?



## RogerS (18 Sep 2010)

I have four Acova Striane radiators on a circuit that is the farthest from the pump/boiler. They've always struggled to get really warm and which I'd put down to my bad balancing. Not any more.

I've put some Sentinel X400 in the system and have turned off all other rads apart from these four. Turned on the heating, whacked the pump up to its' highest and waited. Only one of them actually gets vaguely hot. 

Turning off three out of the four, the rad eventually gets warmish...nowhere near as hot as normal rads elsewhere in the house. Turn that rad off and another one of the four on and the same scenario. Repeating for the remaining two. With all four rads on, they all are tepid. The temperature of the return pipe at the boiler is hardly warm. Certainly I can comfortably hold it. Currently all four rads are fully on and lock shields at max open.

Is this pointing to a blockage in the main 15mm pipe? 

If so what to do? Leave it running and hope the sludge remover eventually dissolves any blockage?


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## gwaithcoed (18 Sep 2010)

Hello Roger, If they have always struggled to get hot from when they were installed I would think it is more likely that you have an air lock in your pipework. 

Alan.


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## RogerS (18 Sep 2010)

That's a very good point. This does then pose the next question!

How do I check and how do I get rid of it?


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## RogerM (18 Sep 2010)

RogerS":310kqlhz said:


> I have four Acova Striane radiators on a circuit that is the farthest from the pump/boiler. They've always struggled to get really warm and which I'd put down to my bad balancing. Not any more.
> 
> I've put some Sentinel X400 in the system and have turned off all other rads apart from these four. Turned on the heating, whacked the pump up to its' highest and waited. Only one of them actually gets vaguely hot.
> 
> ...



Roger - if that doesn't clear it you may need apower flush. This is an oscillating pump that you fit either side of the CH pump and which surges water in both directions through your system, rapidly alternating direction. This clears out the sludge PDQ. gathering it in a container that's integral with the pump. They can be pretty fierce so if you have any weak joints or rust thinned radiator walls be sure it will find them! They are not cheap and a plumber will charge you several limbs to do it for you, but you may be able to hire one perhaps?

If the offending rads are only getting hot at the ends and at the top, i.e. they're cold along the bottom, it may point to a sludged up radiator. In which case you could drain the system, take off the offending rads and flush them out with a hose. Turning them upside down may help shift the sludge whilst doing that. Maybe use a bottle brush lashed securely to a cane perhaps? Just don't lose it in the rad!

PIA I know but cheaper than getting a plumber in to do a powerflush.


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## beech1948 (18 Sep 2010)

This is just a thought.

My experience. I wanted a new boiler and 16 new rads. As it happened British Gas had the lowest price...I know what a shocker...but they did the work, did it well.

However, they did it in two stretches. First the boiler then with a different team a week later they did the rads.

The old rads must of been full of 50 yrs worth of rust, crud and dirt which clogged the fine diameter holes in the boiler core.

So after doing rads we had a power wash ( which they said would cost £800 normally) for free. Only took 2 hrs and washed out a huge amount of crud.

Still had to have a new boiler core which they replaced under warranty.

Since then we have had a device fitted which has some powerful electro magnets inside it before the boiler. WE clean it annually and it is usually full of metal and rust bits probably from lining the old pipework which was reused.

regards
Alan


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## Dibs-h (18 Sep 2010)

Rog - Alan's referring to something called MagnaClean - http://www.adeysolutions.co.uk/

I'm fitting a TwinTech one this coming week. Just over £100 delivered.

HIH

Dibs


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## jasonB (18 Sep 2010)

Roger a lot of these vertical radiators* have a plastic "bung" for want of a better word that fits into the bottom and stops the water tracking straight across from inlet to outlet, if these are not fitted right or left out the water will not flow through the whole radiator. A few also have the bung pre fitted and if you get the rad upside down they won't heat up either. Worth checking if thats the case with yours.

Jason

* Bisque, Zender and Radiator Co have them not sure about your cheap Acova ones :wink:


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## RogerS (18 Sep 2010)

Thanks for all the suggestions, guys. I'd been wondering about a power flush. How does it stop surging up the vent and feed pipes? I think Travis P hire them out.

I'll reverse feed using the mains tomorrow. But even if it does the trick, I do know that the bottom tubes on some of them don't get cold which suggests sludge build up.

Will look into a MagnaClene


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## RogerS (19 Sep 2010)

Rad A gets hot. So too do all the other rads in the house (not shown).

So this morning, fired up the system from cold. Rad A and all others off. Rads B > E trvs off (have checked plunger is free to move and in open position), all lockshields fully open. Started pump and boiler. Went up into loft to watch level in F&E tank. Level in tank gradually rose (as water heated up presumably), No sign of rads heating up. Lots of noise from the loft. Went up to check to see pumping over. 

Turn on some of the other working rads and pumping over stops. 

So this suggests to me a major blockage in the 15mm pipe (flow or return?) between Rad A and Rads B>E? But don't understand why pumping over should occur since the vent is on the negative pressure side of the pump. Unless the pump is fighting against a blockage and one can get back pressure in the pump?

OK....time to test

Test 1 - is the return pipe clear ?

OK... there is a drain cock under Rad E. Fed in mains water and I could hear it flow back down the return. Ergo return pipe is clear.

test 2 - is the flow pipe clear ?

I shut off the lockshield and TRV in E and connected mains water into the bleed vent. Opened up the TRV and heard no water flow. Since rads B, C and D are all shut off, sort of suggests a blockage in the flow to at least rads D and E.

Went upstairs and opened the TRV on D. Then heard water flow and deduce the path is Rad E > Rad E trv > Rad D trv > through rad D and out through rad D lockshield ( ie into the return which we know is clear). 

But rad E will eventually get tepid...with every other rad off. So this suggests some tiny flow? So would running the ch system through this tiny flow gradually desludge it?


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## RogerS (19 Sep 2010)

So.o.o.o one day later..

I removed E and took it outside to flush it out. Quite a lot of black gunge came out. Kept a-swilling and a-shaking until the water came out clean. Replaced it and tried it out. Better but large areas of lukewarm...left it on for the sludge remover to circulate through....not much improvement so far.

I then removed rad D and took that outside. Lots more black gunge but as I have no yardstick to judge by, have no idea if it was normal or excessive. Managed to stain the oak flooring a nice shade of grey. Flushed it out and replaced. Tried it out. Much better but not heating up as much as A (which isn't that far away along the run).

So what have I learned? Tomorrow will go and hire a power flush. Will also order a MagnaClean. Reckon that there is still a bit of sludge in D, quite a bit in E, lots in B and C and probably a load in the flow and/or return.

If that doesn't work then it's floorboards up. Oak, secret nailed..ho hum. Guess that's what the workshop is for.


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## RogerS (21 Sep 2010)

Well the PowerFlush has achieved precisely zip. Rad B flow gets a little warm and so clearly there is some flow through it. So is it a question of time? I simply have no idea. Really cannot remove Rads B or C as it is a pale cream carpet.


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## oddsocks (21 Sep 2010)

Roger, I read somewhere else last year that X400 does the job but it can take up to a month to shift a big blockage (but I would have thought the power flush would do that).

I used X400 last year and after a week in the system I drained and then removed all my radiators (15 years old) and manually flushed them. Loads of black crud came out -and that system had had X100 in from new, replenished every 2 years. The carpets were and still are light cream....I was just careful and ensured all the locks were on, the bleed valve was closed and I had a rag to catch the few drips before each was removed.

If you open the bleed valve does water flow out of each radiator even with the lock shield or temp control valve closed (to get water from either direction)?


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## Eric The Viking (22 Sep 2010)

A few thoughts in no particular order:

1. As mentioned earlier, we originally had three TRVs installed (by a previous owner's plumber) back-to-front. They were in the return, not the flow. It doesn't matter with modern TRVs, but it does with the old Danfoss ones. It took me ages to work it out: drained & flushed each of the offending rads, and checked the pins were free to move, etc. It's worth a check.

2. It's not an airlock - if it was your mains testing would have just worked, as air can't block water flowing!

3. Magnacleans are brilliant. We had one put in early last year, and it's shifted a lot of granular crud. It's now beginning to stay clean, implying all that can be caught has been, which is well worth the investment.

4. Is it possible that the pipework is incorrectly plumbed, for example connecting both sides of the offending rad to the flow, instead of across flow and return? I know from bitter experience that some plumbers don't think! It might be getting tepid just from convection in the pipework, and fooling you into thinking there's a flow and return connected to it.

5. When you had pumping-over, was there a lot of 'kettling' noise from the boiler? It might be caused by actual boiling because the flow is negligible. The overtemp stat ought to prevent this, but sometimes they're either faulty or wrongly set.

6. The more sludge you can remove mechanically the better the chemicals work. I'd take the rads outside individually to flush them (with a jetwash if practical), then I'd do the power flush and finally use cleanser/descaler. Otherwise you're wasting chemical, attacking the sludge rather than it thoroughly cleaning the insides of the pipework and rads. 

7. Our system is pressurized now, but it used to header tank. I was shocked after a hot summer to find a rather thick carpet of algae (pink-orange in colour) growing in the header tank. It had Fernox in at the time and the tank was insulated and covered with the proper lid - evidently the fungicide element didn't work! Point being that the algae would have been an instant blockage, had it entered the system proper. Could that have happened to your system at some time in the past - is there a prominent tidemark in the header tank?

I prefer pressurized systems for two reasons: the water stays physically cleaner, and it can't get a top up of oxygen from contact with the air in a tank. Both these factors ought to minimise crud.

Cheers,

E.


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## RogerS (22 Sep 2010)

Thanks for the suggestions, Eric.



Eric The Viking":3h9fosd8 said:


> A few thoughts in no particular order:
> 
> 1. As mentioned earlier, we originally had three TRVs installed (by a previous owner's plumber) back-to-front. They were in the return, not the flow. It doesn't matter with modern TRVs, but it does with the old Danfoss ones. It took me ages to work it out: drained & flushed each of the offending rads, and checked the pins were free to move, etc. It's worth a check.


 Good point. I just checked a spare one and it is uni-directional


Eric The Viking":3h9fosd8 said:


> 2. It's not an airlock - if it was your mains testing would have just worked, as air can't block water flowing!


 Still a possibilty but getting more remote..our mains pressure is pants


Eric The Viking":3h9fosd8 said:


> 3. Magnacleans are brilliant. We had one put in early last year, and it's shifted a lot of granular crud. It's now beginning to stay clean, implying all that can be caught has been, which is well worth the investment.


 On order


Eric The Viking":3h9fosd8 said:


> 4. Is it possible that the pipework is incorrectly plumbed, for example connecting both sides of the offending rad to the flow, instead of across flow and return? I know from bitter experience that some plumbers don't think! It might be getting tepid just from convection in the pipework, and fooling you into thinking there's a flow and return connected to it.


 No..installed by a top-notch plumber. Moi!


Eric The Viking":3h9fosd8 said:


> 5. When you had pumping-over, was there a lot of 'kettling' noise from the boiler? It might be caused by actual boiling because the flow is negligible. The overtemp stat ought to prevent this, but sometimes they're either faulty or wrongly set.


 Think it was resistance by not having any flow


Eric The Viking":3h9fosd8 said:


> 6. The more sludge you can remove mechanically the better the chemicals work. I'd take the rads outside individually to flush them (with a jetwash if practical), then I'd do the power flush and finally use cleanser/descaler. Otherwise you're wasting chemical, attacking the sludge rather than it thoroughly cleaning the insides of the pipework and rads.


 Rads B and C are in a room with a cream carpet. Removing the rad is not an option.


Eric The Viking":3h9fosd8 said:


> 7. Our system is pressurized now, but it used to header tank. I was shocked after a hot summer to find a rather thick carpet of algae (pink-orange in colour) growing in the header tank. It had Fernox in at the time and the tank was insulated and covered with the proper lid - evidently the fungicide element didn't work! Point being that the algae would have been an instant blockage, had it entered the system proper. Could that have happened to your system at some time in the past - is there a prominent tidemark in the header tank?


 I think it's probably magnetite blocking the feed pipes but getting to it is the problem.

Spoke to Kamco today. I'm doing everything right. Key suggestions he made were tapping with a rubber mallet. I went one better, lifted the floorboards in another room that has also been problematic in the past. Held the rubber mallet on the pipework then used my SDS drill in hammer only mode onto the rubber mallet. Then varied the pressure and impact rate. Seemed to help.

The power flush MUST have at least some flow to work. If the pipe is totally blocked then you're stuffed. Bit like those dams at the seaside you made when you were a kid. A tiny little crack in the dam and as the water flowed through, it carried away more and more of the walls. That's exactly how the power flush works.

Now for the bad news. C*ap maintenenance by the hire company (and I must share some of the blame for not checking as well) meant that one of the pipes came off its' coupling while the machine was on and I was upstairs. End result. Contents dumped all over the utility floor. Have you ever seen a grown man cry ?


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## samharber (22 Sep 2010)

We had our boiler replaced last year and we got the plumber to do a power flush of the radiators, but the one in the bathroom just refused to do any more than get lukewarm. The plumbers advice was to buy a new one as it would be much less effort.

Turns out he was wrong, not replacing it at all was much less effort. :twisted: However - it is starting to get a bit cold in the mornings... maybe it's time...


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## RogerS (22 Sep 2010)

After the mini-flood, I did get B reasonably warm but it took a long time. C remained stubbornly cold despite feeding mains pressure down it. I bit the bullet and had the floorboards up where the junction in the pipe is B/C and D/E. Pulled the flow pipe apart (thank god for Hep2O) and nowt obvious down the leg towards C. I've got one of those metal springie wires for threading cables and that went down OK. A bit rough though. 

Then I tried feeding it back down towards rad A and therein lay the problem - at least as far as rad B taking a long time to warm up. That 15mm feed pipe was clagged up something rotten with Magnetite. Spent a very fruitless hour trying to de-clag it but gave up. So it's major surgery time, carpets up, floorboards up....ho hum.

That will fix Rad B. I think I still have a problem in the feed to rad D and E. rad C we've decided to live with it not working as to try removing it risks the carpet. And I reckon the pipe is clagged up with magnetite.

So...how did this happen? I religiously kept the system topped up with inhibitor and I confess to not having heard of Magnetite before now. Whatever the cause of it, we did not help matters because we kept the temperature down on those rads...to the point where they were barely ticking over. That I think is what caused our problem...system is 20 years old and apparently magnetite settles where the flow is least.


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## Digit (22 Sep 2010)

I'm not sure how old you are Rog but either you're younger than me or luckier. I no longer bury/hide CH pipework anywhere. Once bitten etc.

Roy.


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## Eric The Viking (22 Sep 2010)

RogerS":285syvem said:


> (thank god for Hep2O)



That might be the source of your problem! 

Magnetite is "rust" in an oxygen-depleted water environment and it's formation is significantly affected by electrolytic action. I'm wondering if the absence of a low resistance metal connection around the system might have a bearing on it. One side of the 'circuit' is the water, and t'other side is whatever damp connection into the wall exists for the rad. I suspect that 'isolated' metal radiators will corrode much faster than those in a copper circuit.

If you've had that much corrosion (despite the inhibitor), it would be worth checking the brass fittings either end of the affected radiators too, as dezincification (see: http://en.wikipedia.org/wiki/Selective_leaching) is a definite possibility. I once actually watched a tap fall off the wall because of it: grey cast iron piping embedded in concrete, and the builders had plastered round the base of the brass tap. It snapped off right at the wall, by itself, causing a spout of water into the middle of the kitchen! It was a good thing it wasn't at mains pressure. I was sitting at the kitchen table at the time, having breakfast!

Regarding un-gumming it, can you get some of that springy curtain wire stuff (for net curtains)? If you spread one end slightly and put the other into a cordless drill, you've an improvised long-range corkscrew. 's messy though.

Personally, I'd roll back the cream carpet, put lots of decorating cloths round, and clear the pipework properly. The worst thing would be for one of the taps to fail in that state, as it'd put black gunge everywhere. 

A controlled mess is always better than an uncontrolled one (or so I keep telling her)


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## RogerS (27 Sep 2010)

ETV..you're a star!

I'd completely forgotten about using curtain wire. My original plan was as you suggested namely to use a drill with it. A 2ft length was fine but any longer then it whipped around uncontrollably. BUT....gently inserting it and backing it out bit by bit enabled me to break through the magnetite and clear out several metres of hitherto inaccessible pipework. While having stirred the magnetite around a bit I let some water flow through the pipe which flushed out a load of black gunge. This was what the end of the pipe looked like.





Interestingly, it was the plastic pipe that got blocked and the copper pipe in the same run remained clear.

So I then ran the powerflush unit and had the brainwave of temporarily removing the magnetic core of the MagnaClean and sticking it in the flow of the PowerFlush. Within seconds it had started to pick up magnetite from the water being circulated...






So most rads now functioning. 

I still have reservations about the efficacy of using a Power flush if the pipe is truly bunged up. 

I have even more reservations about the muppet in the hire shop who 'maintained' the power flush. Remember that in an earlier post, the hose came off resulting in brown hot sludge-remover water spewing all over the utility room floor? Well, after discovering that the two jubilee clips were loose, I tightened them up good and proper. 

Halfway through the morning, my builder happened to call me from outside - through the window where the heating pipes were running to the power flush (located outside) - and as I walked towards the window, the pipe shot off again and I got a full blast of - luckily mildly acidic but still nasty hot water in the face, clothes, and a splash in my eye which I promptly rinsed bigtime with my eye bath. Elm architraves bleached beyond recognition, new floor grout now brown. 

So.o.o.o I investigated further to discover that said muppet had done the following. The elbows that attach to the central heating pump isolating valves have sharp ridges on and the pipe is secured to these very firmly by the jubilee clip. This is how it leaves the manufacturer. I know. I rang them up to check. Muppet only goes and wraps slippery black duck tape all over these ridges...so slippery hose on slippery plastic (ridges non-existent)..result..face full. Hire place manager wasn't in on Saturday nor today..Monday. He's in tomorrow.......I can't wait.


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