Per our record the valves are supplied in Year 2013, valve in operation over a period of time the valve torque will increase due to wear and tear.
That is the reason why the valve cannot fully closed over time. The valve are due for maintenance and replacement of a new seat will resolve the problem.
The cost of replacement of new seat service + spare part is USD250.00 each. Lead time is about 3 ~ 5 working day.
The cost of replacement with new valve c/w spring loaded handle is USD1,600 each.
We have the valve in stock and delivery is about 4 weeks, Ex-Singapore inclusive of painting and installing the spring loaded lever.
Attached the drawing and MTR for the new valves.
Do advise your decision, and we will proceed accordingly.