Mach2 sensors are NTC thermistors.
Getting the correct one can be tricky unless you order the one specifically for the Mach2 system though.
They've used a thermistor that's a bit inbetween and unless you have the exact same value you'll be reading off in a different direction.
How much you'd like to keep it right depends how much you'd like to keep your Mach2 where it's meant to be, but if you install a probe and it's not right, at best you'll have a cooler that you aren't sure is reading right, and at worst end up with a cooler that's in error mode because the value is outside what the original one was meant to be.
Best idea if you wanted the controller to read right, just order one from Phil if he's got one in stock, and you're guaranteed that the probe is the correct one.
Cheers
Gray
