In the morning, early, when my thermostat kicks back up, I hear a banging/rattle sound that I've determined is related to my humidifier. It only lasts about 10 seconds so by the time I get down to the basement it's gone. Turning on/off the humidifier doesn't recreate it either. When I turn off the humidifier completely it doesn't happen at all. I thought it may be the solenoid but still scratching my head. Currently I've been turning off the humidifier at night since it's super annoying to wake up to. Any ideas on how to troubleshoot/fix? The humidifier is the basic bypass type. The humidistat is also basic mechanical.
update Solved with a Sioux Chief 660-TC0 1/4' Icemaker Water Hammer Arrestor Tee from Amazon. Thanks to suggestion from user19919 below