From The Ask The Expert Mailbox….


We have a Aprilaire model # 550 furnace humidifier and water

is continuosly draining from it even though our furnace isn’t on.  Is there a problem with it?

Ron, Indianapolis, Indiana



Thanks for contacting us & your question. Water should be coming out of the humidifier drain when there is a call for humidity in the heating cycle. If water continues to come out of the drain, the solenoid valve may be stuck in the open position or the solenoid valve is getting continuous power not allowing it to close. The humidifier pad should be replaced and the humidifier serviced at the beginning of each heating season. Please e-mail or call me at our office at 243-3581 with any additional questions.


Thank you,


Dave Mejean

HVAC Manager

B&W Plumbing, Heating, Cooling, and Drains