This is a Hydrolevel "trifecta".
We used used Hydrolevel's workhorse model 400 series low water cut-off,
the brilliantly designed automatic make-up water feeder VXT-24, and tied them together with
Hydrolevel's 711C specially designed manifold that mounts onto the sight glass tappings.
The old, failed McDonnell & Miller 47-2 we gleefully removed?
Sent to the scrap dumper where it belongs.
Here is a link to the previous video featuring this boiler:
https://youtu.be/yushrKlbLuU