I have 2 hot plates, one is 1000w and the other is 1500w and both are acting strange. One won't come on at all anymore, the wiring is good as it worked some time ago and continuity checks fine but I'm getting strange readings on the temp adjustment rheostats on both units. I test the resistance and my meter jumps all around from 3-4 ohm up to 6-7 Mohm! IDK if that is what happens when pots go bad or what.

Both units are 120vac. the 1500w has a wire from the outlet to the on-off, then another wire from the other lead of the on-off to the burner (splits to LED light). The other wire leads to the rheostat and then another wire from the second connector on the rheostat to the burner (& splits to other lead of LED light). I get constant power through the switch at all heat settings, but the temp cuts off at a "low" temp of maybe 400F. I tried using a fan to cool it but still cut out. This was a new unit 8 months ago. It is a Nesco 1500w.

I think I took the reading for the pot and it may have been 2K or 20K, I forget. I need to know what wattage is necessary for this as well.
https://www.amazon.com/Nesco-SB-01-Stainless-Electric-1500-watt/dp/B00IOMYXLS
The other unit has a 1000W burner and is probably 40+ years old. It is wired the same as above so I assume that it would be the same rating or close, because it is wattage.

Can anyone help me figure out the ratings for replacement rheostat & are rheostat/s the same as pots?

 

Are you sure it's a potentiometer/rheostat? I think it's more likely to be a simmerstat.

 

There's almost no chance that it's actually a potentiometer, since one rated to that power would be far more expensive than the hot plate.