Leaking diverter valve - Vaillant Turbomax Plus 828E

30 Mar 2008
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United Kingdom
My in-laws have a 4-5 year old Vaillant Turbomax Plus 828E that has been leaking / dripping water from the brass diverter valve recently. From what I can see, it appears to be coming from the small hole (not sure what its called) that is on the side of the diverter valve itself.

There is still a supply of constant hot water but the water pressure drops slowly.

Is there any reason why this should have happened? If required, would I need to drain the system prior to replacing it?

I've seen replacement brass diverter valve for approximately £70+vat. Does this price sound about right?

Thanks in advance folks.
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The original diverters had a few issues, replacements are improved and seem to be more reliable.
Just turn boiler off at isolating valves undo the nuts and catch water in a basin in and out in 15 mins max
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That is the first time I have heard of the seal in that diverter valve failing.

If you are going to change it then look at the colour of the water. If it has a blackish tinge to it then there is magnetite in the water and that will be likely to destroy the new diverter valve as well after some time.

The water may need to be flushed out to prevent future problems.


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