Replacement stuffing box/stem seal
When leaking by the gland, a stuffing box replacement may sometimes help.
The DN125 to DN150 of the V321 valve was changed around mid 2007 (the other sizes remained unchanged). With this change the valve stem changed from diameter 18mm to 12mm.
Fortunately the stuffing box from the V222 and V292 valves of DN125 to DN150 also fits the V321 valve, thus gland kit 100108210 should be the correct gland kit to use if you have the old valve (stem diameter of 18 mm).
If you have the new V321 model (stem diameter of 12 mm): Replacement/spare stuffing box for V321 DN65-DN100 is part no 100108220 and for DN125-150 it is part no 100108230.