Automatic water top off device?

topoff

We have 2 Superior boiler SE-52 units, one for each apartment in our 2 family home.  We have to top them off periodically throughout the Winter to keep the heat running.  We do not have any leaks in the boilers themselves, is it normal to have to add water?  If so, how frequently would one expect to do this in New England in the Winter?  Is there a device that can be installed to automatically top the boilers off to prevent them from running low?  Thank you very much!

Charlie from wmass

automatic water feeder

Depending on the boiler I use a VXT 24 or a VXT120. Adding is normal but excessive is not good. once a week maybe 1/2" OR LESS. anymore I would say start looking for leaks such as air vents or radiator valves.