Draining Central Heating/Combi Boiler ; Vailliant Ecotec

[Terry34673]

I did this recently via the bathroom towel radiator and I made a terrible mess with water all over the floor. I am sure there is a dedicated outlet valve/pipe to the outside from the boiler which I saw a plumber draining the system to a while ago. Which valve would I turn underneath the boiler to do this? I have looked a few times but can't see anything obvious :

Outlet / draining pipe on wall behind boiler

Valves under boiler

Thankyou !

 

[Phill Peck]

None of the valves under neath are connected to that pipe.

It's a safety valve and shouldn't be used to drain the boiler.

You want to drain the boiler only? Why? Or the system?

There will be drain valves on your system at the radiators.

You can drain the boiler only but you should have no need to drain the boiler only as you shouldn't be going in there.

 

[muggles]

The pipe to outside is a safety pressure relief and should never be used to drain the boiler, as you risk damaging the pressure relief valve. The left hand valve in your pic has a connection to accept a small hose for draining. What are you proposing to do once you've drained it?