Leak sealers - Are they all the same or are there rubbish ones to avoid?

[Cordless Crazy]

Gonna be getting some of this gear to seal a leak which I can not get to without hacking my new bathroom to pieces. Long story, but it feeds the towel rail, which is fed under a newly tiled (and UFH) floor, then up a wall sandwiched between a bath and a cupboard.

Tending to sway towards Fernox as it is top of the range, but will the Sentinels and other cheapo brands (eg Screwfix No Nonsense range) be just as good?

Either way, is the injector tube the better one to go for, from an installation point of view? How exactly do they fix to radiator bleed valves without the water pi$$ing out all over the place?

[Dave Plowman (News)]

You shut off both lockshield valves and drain down the rad at least partially and the filler tube screws in place of the bleed valve. It is easier if you can disconnect the rad at one of the lockshield valves as otherwise you're trying to force in the gunge against air pressure.

[The Medway Handyman]

Dunno, but the difference in price isn't enough to worry about compared to the agro involved.

The injector tube can be used on a combi system, the liquid ones have to be poured into a tank.

I've used two types of injector systems, with both you turn off a rad both ends & inject the stuff into said rad via a bleed valve & it then disperses around the system.

One type comes in a cartridge & is used with a mastic gun. The one I used (Fernox I think, long time ago) didn't mention draining a little water from the rad, but you do need to - you can't get 300ml in without draining 300ml out.

The other one was from Wickes & you buy a rubber 'bulb' type pump with plastic tubes each end & a liquid leak sealer. You use the pump to pump out water from the rad via a bleed valve then reverse it & pump the sealer back in.

Both worked & stopped the leaks, I reckon the Wickes one was easier to use.

[Colin Wilson]

The screwfix variant worked fine on my system fwiw

[Heliotrope Smith]

You must be sure that the towel rail is fed from the heating primary circuit and not from secondary hot water.

If the latter is the case then it will not be possible to dose it up as it is the same water that comes out of the tap.

Steer clear of very cheap sealer as some are not very effective. I think you would be better off going for the fernox stuff.

The super concentrate inject type is easy to use as there is no draining water off and the possible problems of air locks when topping up again. This comes with a variety of attachments to fill via radiator vent pin or plug or filling loop if you have closed system. Filling through the loop is the easiest and quickest.

To fill through the rad turn off both valves and remove the pin or plug and set up the cartridge in the mastic gun and connect to the rad, turn on one of the valves (it won't work if you don't) and pump in the super concentrate. When that is done turn off the rad valve again and remove the adaptor and refit the plug or pin again turn on both valves again, job done in less than 5 minutes and no mess or air locks.

[David]

Sentinel one worked fine for my Grannies system.