C-Tec Miracle seal for leaks. Anyone used it?

We have a leak in underfloor c/h pipes (under concrete) and have just found this stuff with its marvellous claims. Seems to come in 250 ml cans, to treat 25 litres but a c/h system for 12 to 15 rad's contains about 100 litres, I think. Other treatments (cleaners, inhibitors) treat up to 125 litres so I'm guessing here.

Has anyone tried this stuff for sealing a leak? Esp. a c/h leak?

 

As you know where the leak is you could shut off all radiators both ends while you run the stuff through to save the amount you need to add. Never tried it myself.

 

It is intended for emergency repairs. Personally, I would not waste my money.

MSDS for the product is very difficult to track down as different links produce different sheets. The important component(s) appears to be a silicone polymer or monomer, depending on what potential ingredient you trace backwards. I see no reason why it should preferentially lodge in any leak, adhere and, most importantly, remain there.

I did not see any indication as to what size hole it might plug either, and it must have some limitations, no matter what it might actually do (or not).

 

I stopped a leak in my car a couple of years ago with a similar treatment for cars. I think if it's only a small leak it could well work but it will not fill up any gaping holes. I don't mean big holes, just a couple of mm would probably be too much for it. It's up to you but I personally would try adding just one can and see how it goes.....you never know.

 

I would not put anything in without first speaking to Vaillant to make 100% sure it won't affect the new boiler's warranty. And maybe best to get their reply in writing too!

The reviews on some of these leak sealers look good https://www.screwfix.com/p/sentinel-internal-leak-sealer-1ltr/99730 Even if it gets you through to the spring so you have more time for a proper fix when warmer.

 

Sorry. Haven't a clue where it is except that I'd imagine it must be gnd floor under the concrete; however, still a viable suggestion. Did you mean close ALL rad's? up and down so that only the actual pipes are pumping round with stuff in? Sounds sensible 'cos the leak's not in the rad's.

Any port in a storm, Vinny; even if it's temporary (and does work) it'll be worthwhile. The alternative?????? (horrible).

Used seventies equivalent many times in various car rad's; hopefully things have moved on a bit from them.

Am phoning Vaillant about this and other things. A big ask to get it in writing though !!!! They should do what's on the tin, but my plumber will prob. apply when he comes round tomorrow week. At the mo' (and 'cos it'll be v. cold this week) we're keeping the htg on 24/7 for 4/5 days, as it doesn't leak as long as the boiler flow temp is above 50 degrees.

Hobson's choice here; more htg that normal or even needed or wasting up to 5 litres an hour of cold mains water which trips the boiler/pump in the small hours as the pipe water cools rapidly.

 

You've said that you have suspended concrete floors, which the pipes run under and you reckon this is where the leak is.

How big is the gap between soil and under-side of the concrete floor? You have also said that the pipes were not originally insulated (probably the same as here, but under suepended wooden floors - very old rubber foam that has perished and fallen away?????), which implies that the gap is accessible. 20 years ago, I'd have sorted this sort of hassle myself, and I am younger than you, but maybe not now, but if the gap is accessible, checking things either by eye or selectively freezing sections and doing a seepage test, is the way to go?

You have had insulation added to the pipes under the floor, so doing a repair, once the leak is found, ought to be no greater task????????

 

Do you know the route the pipes take underground? Has there ever been an extension or a radiator moved in the past? Remember me saying that I have had a similar thing.. it transpired to be an extension which had pipe corrosion… now this extension was done in the 80’s, and the pipes used were thinner, worse quality copper which didn’t like being underground.. the original, 1970’s, copper is still underground in part and (touch wood) no leaks…

Maybe worth a quick mental check?

 

As to my comment about shutting all radiators, yes I did mean all - maybe leave one open as a heat sink. Then one pot should do it, and pretty quick if the youtube vid is to be believed. If it's one pot for 25 litres, no point buying 4 just cos of radiator volume. I am no plumber by the way, this just seems sensible if you suspect it's the pipes not the rads.

 

It’s very sensible!

 

Dunno what these are, Vinny. Simply concrete screed laid onto subsoil/stones whatever. Many pipes accessed 08/09 for interior building work, moving plus new rad's and laying my hifi conduits, so can remember roughly where the pipes run. However, there's no way ANYTHING is accessible without removing carpet/underlay/total hifi installation and shelving etc. and excavating the concrete. No way Jose, even though I did do some of that excavation when I was young and foolhardy.

Only a short (new) length was wrapped. The rest is as was; bare pipes.

See above, Rug Doc in my answer to Vinny.

 

Beyond suspicion. Besides, any leakage from rads or their feeder pipes would 've been evident long before now.

 

Well that’s crap news. I would 100% wait for the engineer to come and get him to insert the sealant.

Does one side of the house have healthier plants in its borders??!

 

No way will a boiler manufacturer tell you that its okay to put leak sealer into a system and there's even less chance they'll let you have it in writing.

Mike you can't bodge this, sorry, the leak has to be found and fixed if you put leak sealer into the system then you'll void the boiler warranty because if the boiler's HEX fails or blocks up the first thing, or one of them, a manufactures engineer will do is to take a water sample from the heating system.

 

From previous descriptions, I had assumed that the concrete floor was suspended as you implied that there was no DPM in it. There must be a DPM in the floor if it is laid onto the soil, and normal practise would be for pipes to be above it - it would make no sense to pierce the DPM for pipes. Hence my previous comments, including the fact that with this system, there would be a very wet floor somewhere. UNLESS you have a damp-proof layer on top of the concrete - back in the 50's it was common to use a bituminous adhesive and plastic floor tiles as the DPL, but not very often since, and as your floor is new....... That said, a surface DPL would probably have been pushed off by this amount of water - the adhesive would fail.

A suspended concrete floor is the same as any suspended floor - a gap between soil and floor. Suspended concrete floors would normally be installed as pre-cast beams, but could be cast in-situ. Your description previously did sound very odd, but never say never.

 

No way I'm going to chance this with a new installation; shall await the plumber in a week's time

As I would've guessed, Tony; I'm sayin' nowt !

Agreed, but finding, let alone fixing the leak (esp. at this time of year) doesn't bear thinking about. I't down to the plumber as to what action to take or advise, but I'm a bit miffed that he doesn't consider this to be other than routine (I assume). This week it's c/h 24/7 , simply to stop wasting water and to monitor things 3 x a day in the loft (luckily my wife is fairly agile as we only have a large wooden step-ladder !!!!) and flow temp's.

What you're saying makes sense, Vinny, but the only bits I've seen are where the concrete was excavated, in longish pipe runs, and I can't remember much except roughly where they are. There must've been a gap under the concrete, but no obvious membrane or 'joists'. I do remember bitumen though; in places at least.

 

Do you have a hot water tank??

One thing I would do would be to shut off the Ch pipework with a valve or two (after going through the immersion heater) to primarily remove the immersion heater as the culprit - it could have a leak internally…

if you isolate the CH pipework and it still leaks then happy days.

 

you have a DPC on top of the external brickwork as usual. and then a poured concrete floor straight onto the ground with a bitumen dpc painted on top of it… then a screeded floor on top of that.

 

Mike, frankly I think your plumber is 'at it' I'd advise you to contact someone else and send the plumber a letter telling him that you're doing this because he hasn't been accommodating and that'll you'll be expecting him to pay the bill for the third party otherwise you'll take him to court to recover your losses.

Personally I think the guy is bloody out of order.

 

Agree. He's recently done an install, having to wait over a full week in Jan for him to tip out and inspect a fault is unreasonable.