Hi! Our digitally controlled muffle furnace is currently under repair and so we are relying on an old standby, a Fisher Isotherm Muffle Furnace 184A. Does anyone have tips on identifying the temperature setting on the numerical dials? Today, the oven was set at a "medium" setting (dial was turned up halfway) and when I returned to check on it a few hours later, the oven was at max temperature (1100 degrees C). I only need to ash some samples at 450 degrees C.
Anyone with experience with this particular model, I would appreciate any tips. Hoping to get the newer, digital furnace online again soon!
It sounds like your old Fisher 184A muffle furnace requires calibration, which isn't be a surprise given its age and that you presumably haven't used it in a long time.
You could theoretically compensate for its lack of calibration by turning the analog dial to different values and seeing what temperature that equates to. Document the results, do it twice to ensure it's reasonably repeatable, then you'll hopefully be able to use it.
You also might be able to get a technician in there to repair it, but that might be a tall order given the age of the unit. You also probably don't want to spend $1000 on the old backup muffle furnace having it repaired.
Hopefully the old furnace wasn't too far gone and you figured out the temperature settings!
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