I'd like to know if during a yearly maintenance check on a natural gas boiler includes turning off ( temporarily) the auto feed valve during a system flush prior to season start up. What would happen if this valve was left off for the entire heating season? We did not have it in continuous use, only a few hours at night when it was cold. It worked all season and actually started up the other day but we realized that there wasn't any water in the system when we saw the sight glass was empty and shut it ( the boiler, not the water valve) down immediately. We have another gas fired fireplace used most of the time. When the service tech came he saw the valve was off and turned it on, water poured out from under the heater. We believe he forgot to turn it back on last year and that there was enough water in the system to keep it running. We did not turn it off at any time. They are not taking any responsibility!! Any response

a steam boiler is supposed to have a float that senses when the water is too low and will shut the system off. it will not run when there is no water.