Problem With Coupling Devices
There is a problem that is created when the installer of a steam boiler uses a replacement boiler that has an electronic low water cutoff but re-uses the existing 101A mechanical water feeder.
All will seem fine as long as the power to the boiler is not interrupted. If that interruption does occur, and it will, from either someone working in the house, or more likely from a storm, the water feeder will feed water during the whole start up period where the electronic low water cutoff is resetting itself. On an average sized boiler, if this happens more than once you will likely flood the boiler and may even generate a 'no heat call' because of it.
An electronic low water cutoff should only be coupled with an electronic water feeder, or a mechanical feeder that uses a float as its activation method instead of an electrical signal.
Check out this video to see it in action.