It’s funny how the smallest things can cause such problems. I woke up on Sunday morning, expecting another uneventful day. Maybe I would finally get around to tearing out that sheet rock around the shower head and figuring out what’s wrong there. Unfortunately, the furnace had other ideas.
Before we get there, though, it’s probably instructive to share something. I have what is apparently a freakishly unusual sensitivity to the sounds made by machines. I often don’t feel completely comfortable in a place until I at least have some idea what is making all the sounds. Here at the house, I can identify pretty much every sound (along with the purpose of the device making it). On more than one occasion, Amy has witnessed me wandering into the computer room from across the house and sticking my head around various places with a puzzled look on my face. When she gives in and asks what I’m doing, the answer is something like, “One of the fans buried in one of these computers is about to go out.”
So, here’s a trip through the routine that goes through Jeff’s mind several times a day:
“click”: thermostat asks the furnace to come on
“whir”: furnace combustion blower spins up
“rumble”: gas burners light
“whoosh”: circulation blower is moving warm air through the system and the house
Early Sunday morning, I heard “click”, “whir”, “rumble”, but then “rumble” went away. Several seconds later, “rumble” came back, then it went away again. Finally “whoosh” showed up, but the air wasn’t warm. Great. So, there it was a Sunday morning (when I couldn’t call to get it fixed without spending a bundle), and the furnace was acting up. Better than that, it was the morning before the night that it was supposed to be 16 degrees F (-9 degrees C). I could hear the pipes begging for mercy already (not to mention the cats).
So, I hauled my butt up into the attic (which involved the Dance of the Cars in the Garage™). Of course, by the time I got up there and got the panel off, it was working great. I nosed around a little bit with the multimeter, but I wasn’t going to be able to find anything unless I saw it happen. So, I came back down. Noticing that I’d been criminally negligent in not replacing the filter lately, I did that next, hoping maybe that was causing the over-temperature sensor to trip. No more problems until that night. I got my hopes up.
Click”, “whir”, “rumble”, no “rumble”, “rumble”, no “rumble”… back up into the attic. To make a long story short, the computer buried in the furnace thought the burners had never lit (it’s deaf, so it can’t hear the “rumble”). Either the computer was senile (bad… it’s expensive and probably not in stock within 100 miles), or this thing, called a flame sensor, wasn’t working. Basically, the flame conducts enough electricity that the computer can “feel” it using this sensor (which doesn’t seem to be much more than a metal rod connected to a wire).
Back downstairs. At this point, I figured paying a large sum to get emergency repairs was better than paying an astronomical sum to fix broken pipes. The bad news was that the first guy I called was literally booked all night. However, he provided hope. He revealed that the flame sensor can often be at least temporarily revived by giving it some gentle persuasion with sandpaper. So, it’s back up in the attic again. The thing was easy to get out, so I started sanding it. I also noticed that the porcelain insulator was broken, so the thing could actually spin around in its bracket (which was probably the problem). Part went back in, got gingerly aimed in the flame, and the furnace worked.
So, my night was spent with an alarm going off every couple of hours to make sure that the “rumble” didn’t go away once it started. First thing this morning, my quest was to call the local heating repair places to buy one of these things. After an hour and a half of “not in stock” and “we don’t sell parts…but we could come fix it”, someone finally broke the HVAC repair code of honor and said “Have you tried the Trane parts dealer? Here’s the number.” (unlisted, best I can tell).
*deep breath* So, at 11:00 this morning, I finally managed to replace this $6 piece of metal and porcelain and get on with my life. I shouldn’t complain. If I had to pick a part to go bad, this is the one I’d pick. I do wish it hadn’t decided to die on a weekend, though.