Vent: Our furnace temperature controls are all over the place lately
I've been dealing with this for weeks now. The digital readout jumps by fifty degrees without warning, so we can't keep the pours steady. We've called maintenance three times, but they just reset it and leave. It's messing with our whole production line.
Sounds like a bad sensor or loose wiring in the control board. Had a similar thing happen at my last shop. Tell maintenance to check the thermocouple connection, it gets corroded and sends wild readings. If they just reset it again, go over their heads because that's a band-aid on a broken pipe.