Leak Sealant in central heating system? Does it work?

AWomanNeedHelpPlease

I previously posted about my Vaillant boiler pressure drop. I call in a gas Plumber, he look into the boiler and suggested leak sealant.
May I ask anyone has use this method before? How long does it take for a Plumber to pour sealant in? My plumber ask me to book he in another day cos he hasn't got sealant in his van. (he only in my flat for half an hour but I have to pay for his visit which suppose to cover an hour).
Since he find no leakage on boiler and can't see any leakage (but he hasn't walk around to check radiators, I only have five radiators in total.
I also show him pictures I took from downstair basement flat which show sign of damp patch on ceiling but he didn't pull out the floor broad to look into it.. ( the floor was pulled few years ago for washing machine issue )
Maybe, from his experience, he know a sealant is all it need. I don't know, that why I seek for advice here. Any suggestion or share experience regarding these matter will help me to gain more knowledge to deal with the Plumber.

alanobrien

i have used it in the past.
If its a small leak it should work but its not a permanent fix.
It should take no more than 30 mins to put it in a rad then circulate it around the system.

markin

Ive read that it can also block up the heat ex-changer on the boiler, not a cheap part to replace.




Its probably a diy job if you really want to do it.

https://www.screwfix.com/p/sentinel-ls-rapid-dose-leak-sealer-adaptor-300ml/7013v

southcoastrgi

Where does he think the leak is then ?
How can he not check the rads if you have a leak ?
You will be charged for a full hour especially the 1st hour even if he was only there for 30 mins but I might suggest you look at asking another engineer as yours doesn't seem bothered.

If you are going to use leak sealer CT1 miracle seal is the best out there

bris

Leak sealer is for a DIYer, and decent engineer would find the problem and fix it. As above what engineer looking for a leak doesn't check the radiators?


A damp patch on the ceiling below pipework would also be a bit of a clue and need investigating.


Personally I would get a second opinion as I wouldn't want leak sealer to repair a leak in the boiler.


Did he check for a leak into the condensate? A heat exchanger can leak into the condensate drain and not be externally visible.