M52L is obsolete and needs to be replaced.
Replacement of obsolete actuator.
The M52L on a V354 or V355 is replaced by MC52A or MC52B:
-MC52A , part no 8532221010, modulating control
-MC52B-24, part no 8532320000, 24V, Inc/Dec
-MC52B-230, part no 8531320000, 230V, Inc/Dec
These part numbers does also include an adapter ring that needs to be used when mounted to the V354 or V355 valves.
Please note that the suggested replacement actuators listed above does NOT carry a 16V output. If this feature is required, an external 16V supply must be provided.