What causes air to build up in hot water boiler over night,installed new boiler as of late,there are no leaks in system.when we use the hot water in the morning,it will constantly sputter with air escaping in the water,then its OK until there is a long period of no use like over night,thak you in advance for any help you can supply

Would this be a hot water heating boiler or a water heater? Gas or electric? Doe you hear any noise when it's running? Back to you. Tom

Its an electric hot water boiler [40 gal] recently installed,there is no noise from boiler,just air builds up when its not being used like over night,and there are no leaks in system

I wonder if the dip tube, located under the cold water inlet, wasn't either left off or dropped down in the tank. Is the water as hot as you would like? What temperature is it set at? Regards, Tom