Honestly, I’ve seen heaters pull that “I’m running when I shouldn’t be” trick way too often. Here’s my quick-and-dirty checklist:
- First thing—kill the power. Trust me, you don’t want a surprise zap.
- Double-check the thermostat wiring. Sometimes people get creative with wire nuts and things get weird.
- Give the relay a little tap (not a whack). If it clicks or changes behavior, you’ve probably found your culprit.
- Multimeter’s great, but don’t forget to sniff for burnt smells or look for heat marks on relays and boards. Sometimes your nose knows before your tools do.
- If all else fails, I’ll admit: I’ve just swapped out a relay on a hunch and it worked.
Funny thing—one time I traced a “ghost voltage” back to a mouse nest in the wall. Chewed wires everywhere. So yeah, never trust tidy wiring alone... those critters are sneaky.
In short: trust your meter, but don’t ignore what your eyes (and nose) are telling you.
That mouse nest story hits close to home—critters are the worst for mystery shorts. Ever had a relay stick closed even after you replaced it? I had one where the board itself was sending voltage when it shouldn’t, turned out to be a hairline crack on the PCB. Curious if you’ve run into weird board issues like that, or is it usually just relays and wiring in your experience?
I had one where the board itself was sending voltage when it shouldn’t, turned out to be a hairline crack on the PCB.
That’s wild—hairline cracks are sneaky. I’ve mostly dealt with relays and bad wiring, but once I had a furnace that kept running because a solder joint on the board was barely hanging on. Took forever to spot. Critters are a pain, but those tiny board issues can really mess with your head. Sometimes it’s not the obvious stuff at all.
Yeah, those tiny board problems are the worst.
Couldn’t agree more. I once spent half a day chasing what I thought was a stuck relay, only to find a tiny scorch mark on the board from a loose wire arcing. Felt pretty dumb after, but you just can’t see that stuff unless you’re looking for it. Makes me double-check the board every time now, even if it seems fine at first glance.Sometimes it’s not the obvious stuff at all.
That’s wild—tiny scorch marks are sneaky. Makes me wonder, though, do you think those little board issues are more common in older systems or is it just luck of the draw? I’m always torn between fixing things myself and calling someone in, especially when it comes to anything electrical.