I am trying to replace the powerhead with 40003916-001, which is a replacement powerhead matching this valve according to the instructions with the powerhead and this url
I have removed the 2 screws attaching the old powerhead to the valve and expected the head just to lift off, but it seems to be firmly secured around the activator mechanism. Is there something else I need to do before I can remove the head?
Are you sure that your old valve is the type with a removable head? If it is, there will be a small "bump" on the top of the metal cover - the new actuator will have one.
If there is no "bump" you will have to drain down and modify the existing valve body using a plate and ball assembly kit - part no 40003918-006.
If there is a "bump", try locking the lever in the MAN position before removing the head.
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