How is it that the performance of a Torbeck valve can gradually degrade over time, and yet when the time comes to look at it, nothing less than a full strip-down and service will do?
Surely it should be possible to just back-track a little to the point where it was not failing?
But why bother? Toilet with Torbeck valve requires attention every year.
But downstairs toilet (qv) with traditional ball-valve has given trouble-free operation for over 10 years.