Hi, I have an 18 month old Vaillant ecotec 831 combi boiler and I'm getting very hot water out of the cold taps in the bathroom but not the kitchen. The pressure is high too, around 2.5 bar. The cold water supply seems to be different for the bathroom versus the kitchen; I can turn off the cold water in the kitchen with a stopcock below the sink but can't find a stopcock for the bathroom. Any help much appreciated, thanks

Hi FH...

Most likely you have single lever bath faucets and probably a single lever shower valve, too.. right?

Here, you probably have a mixer cartridge that has gone bad and is letting hot water cross over into the cold water.

To test which faucet is at fault you really need to be able to isolate each valve using shutoffs. However, you said you couldn't find any except at the kitchen faucet. That will complicate this, for sure!

Let me know more about your faucets/valves in the bathrooms... OK?

Mark

PS: I pop in and out at different times so check back periodicaly... OK?

Many thanks for your answer. I forgot to say I live in an old apartment block (20 odd apartments built 1920s) and the bathroom water supply comes from a communal cold water storage tank on the roof (so a different water source to the kitchen, which comes straight from the mains). I think someone else might have had some plumbing work done (shower or boiler) in one of the other apartments that's gone wrong and their hot water supply has somehow crossed into my cold water - sound feasible?
Thanks

Sounds reasonable, but remember if you have any single handle valves the issue could be within your unit, too!

Check with your neighbors...

Let us know how you make out, OK?

Mark