I was inspecting a Lennox furnace and brushed against the coil on the side of the gas valve. It was hot enough that it made me jerk a little. It measured about 164 F with the IR thermometer but I didn’t initially think anything of it. The next day, yesterday, I happen to come across the very same furnace, photo is below. After running about the same amount of time (15-20 minutes straight), the coil on this gas valve was only at 76 F.
So now I’m wondering if the first one was overheating or if it was normal. I’m not familiar with the purpose of the coil so I’m at a loss. Any HVAC guys out there who could shed some light on this?
I got about ten feet away from the exterior condenser and noticed an audible hum coming from it. When I got up to it, it was loud. Not as loud as the transformer boxes throughout the neighborhood, but the same kind of humming or muffled buzzing. I can’t remember anytime in nine years where I noticed a unit humming away when it wasn’t operating. Any thoughts? Bad transformer inside?