Oily Leak Residue from Gas Boiler

1 Oct 2016
Reaction score
United Kingdom
Evening all,

Had the gas man out today to check over a small intermittent leak on my Baxi 24HE condensor system boiler

He's spotted that the leak is coming from the condensate trap or the pipe leading to it. Replacement is happening.

The weird thing is that the residue that's built up on the bottom of the cases is really oily feeling, and kinda acidic on the tongue. Looks a bit like white grease. It's clearly been weeping for weeks or months so has had lots of time to evaporate the water off - i.e. is super concentrated.

Gas man isn't concerned and I trust this guy but I'm really curious *why* the condensate would evaporate to leave this greasy residue. Never seen anything like it near e.g. a gas hob so I'd assumed the boiler burns as clean as that and condensate would be almost pure water...Not getting many hits searching google or forums though!...

Is this normal? What is the residue and why does it happen?

Thanks in advance!
Sponsored Links
Condensate is slightly acidic,and can also carry impurities from within the boiler. It may have reacted to any coating / paint on the boiler casing......maybe.
Where we didn't spot it for a while the few drops that got out have etched slightly into the black epoxy countertop underneath it so the acidic part of the story does make sense. It was greasy in areas away from paint though (bottom of burner cabinet, on the worktop underneath) so I'm not convinced the oily/greasiness is paint related, but I like your thinking...
Sponsored Links

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local