Leak sealant - anyone used it?

[CandyKate]

Hi there, we have a small leak in our CH pipes that is causing a small brown stain at the top of one of the ground floor walls. We have checked bathrooms/showers above etc and there are no leaks from there.
I have been recommended liquid leak sealant. Will this work? And where do I put it into the CH pipes considering that I don't know exactly where the leak is. The boiler?

Our plumber used leak sealant to nurse our dying boiler through its last 2years, as we were planning an overhaul. It did work, but was not perfect. (boiler now in skip in the sky!) It needed done each year. Our leak was in the boiler itself and it did leak occasionally (we just had a permanent bowl underneath).
So I'd say it was a short term imperfect fix that might tide you over. I would only recommend if you have a good reason not to go it properly and if /when the leak reappears it won't cause damage anything else.