Furnace clicking (not used in over 3 weeks) when running A/C
My furnace started making a constant clicking sound when not using it. The A/C was on cool. Fan set to ON. There is no "auto" setting other than for the fan - it's either on or auto. The other control is either cool-off-heat. I was running a vacuum at the same time. Couldn't get the clicking to stop unless all power (fuse, battery, electric plug) was disconnected from the camper.
A week later and I can't get it to do it again so the repair person can check it out. Thoughts??