When it comes to heating leaks, leak sealant is usually recommended as the “quick fix” by plumbers and boiler maintenance companies due to it being cheap and easy. Although effective on small leaks it is only a temporary fix, long term it could cost you a lot more when having specialist leak detection specialists out.
When the leak does start to appear again and you call out specialist leak detection engineers, it can be difficult for them to use tracer gas to detect the leak in the system as the tracer gas can cause the sealant to temporarily plug the leak. Once the system is refilled the leak will come back again. This means leak detection engineers will have to come back to the property and a second fee will apply which can be quite costly. This is why it is always best to get leak detection carried out before adding leak sealant.
However, if you have added leak sealant before having leak detection carried out there are other ways around to clear out the system. For tracer gas to be used as an effective method to detect the leak you will need to have a power flush conducted to flush the leak sealant out of the system.
In some cases, leak sealant can invalidate the warranty on some new boilers. Also they will only end up causing you a lot more hassle, and costing you more!