Is the pump sized properly and operating at full capacity?
The pump should be sized to pump at least 2 times the steaming capacity of the boiler.
Pump capacity is reduced if the pump impeller is worn or seals/packing leak.
Have the system dynamics changed from original installation?
The water level will drop faster if additional load has been added or if boiler is
operating at or above its rated capacity.
The boiler water level will fluctuate widely if valves that slowly opened before have
been replaced with quick opening valves.
Is system piping clean and in good condition?
Clogged strainers can reduce the flow of water into the boiler causing the boiler to
turn off on low water.
Partially closed valves can reduce the flow of water into the boiler causing the boiler
to turn off on low water.