The 40003916 power heads enable the complete power head assembly to be replaced, without draining down, on V4073 Mid Position series valves.

On older style valves, which did not have the replaceable head feature, the adaptor plate assembly can be used to upgrade the valves to allow the replaceable power head to be used.

Installation

When making a like for like replacement of the power head only,
ensure that the Auto/Manual lever on both the installed and replacement
power heads is in the Manual position.
The power head is held to the valve body with two fixing screws which are
held captive in the power head base. If upgrading an older style valve it will
be necessary to drain the system water level to below the zone valve.
The adaptor plate assembly is held in position by four screws (supplied).