Milky water in Vaillant condensing boiler Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[oldwelshman]

Hi.
I have seen a post on this previously but cannot find it in search so have to ask the question again sorry.
I have a ECOmax 824 Vaillant condensing combi bolier.
I have had a few faults which I have resolved and wish I had replaced the poxy thing.
I have an intermittent leak, yes and intermittent leak :D
I get a milky coloured water in my boiler.
I found out it apperas to come from the back of the bolier at the back of the main heat exchanger and loos as if it is from area between the heat exchanger and the condensate unit though I cannot see exactly where from, but the water runs down the black corrugated pipe that goes outside.
I left the covers off to check and left a little tray to catch the water to stop it going to front of boiler where it can short out one of the sensors !!
I notice the leak becomes worse when the boiler fires upo for DHW.
The pressure in the bolier does not change so I presume this must be some sort of leak of mains water from the main heat exchanger.
Is this likely to be a seal problem between the heat exchanger and the condensate unit or am I looking at a new heat exchanger?

[htg engineer]

If it was a leak from the main heat-exchanger then the system pressure would drop, obviously depending on how much water you're losing.

From where you have described the leak is coming from it sounds like it's a leak from the flue or secondary heat-ex but definately leaking condensate.

How old is the boiler ? still under warranty ?