I don't know the answer to that, and I'm not where I could look at it today. However it works, it seems to be very consistent. I have checked it many times with the laser thermometer and it gives the same numbers based on the gauge time after time.
ok, Reason I ask is, I was in the HVAC business for many yrs. I also worked on appliances (ranges, fryers and such)
These appliances (like some others) have thermostats that operate off a bulb with a liquid inside that expands and puts pressure on a diaphragm to control temp. like these mechanical gauges operate
Over the yrs with the expansion and contraction these thermostats will began to get out of calibration and have to be replaced.
Just wondering if it's possible for this to happen to these old temp gauges as they work about the same ?
Another subject is, measuring the temp an laser (infrared thermometer) When they first came out, many HVAC companies bought them thinking they would be accurate in measuring them. on refrigerant lines and other parts of the HVAC system.
We found them to be inaccurate at measuring temp on HVAC units.
Depending on where you shot the laser on the equipment, you would get a different reading. On top of a pipe would give a different reading than on the side of the pipe, etc, another reading.
I'm not saying I wouldn't trust your readings with that laser, but I would verify.
It wouldn't hurt to purchase a new mechanical gauge at the auto parts, on line, etc, (with actual numbers on it) and install it to verify your temp is within range
But if you are satisfied the temps and gauge are operating properly. then. just leave things as is and run the tractor
Good luck !
