Water exitng overflow pipe

[Smileysmile]

Recently water has been exiting my overflow pipe onto my garden patio.

I believe the water tank in the attic is the CH tank.

Can anybody from observing the attached video clip give me advice how to resolve this.

The water entry you can see slight drips when the ball cock should when at its highest point should close any water entering the tank. Much appreciated

 

[Scally-Ho]

That ball/float valve probably needs new washer and then the water level lowering a couple of inches. To do that the arm needs carefully bending