Cooling issue, but this time it's to cold...

Right I know you can get bad new parts,it's happened to me before. But even without a gauge if I can't get enough heat to run the heater ??? I will check the water temp with a meat thermometer. I did check the t-stat in water on the stove this morning, it started opening at 185 and was fully open at 210.
I'm waiting a bit to reinstall it for advice here, after that I can put it back in and check the temp in the radiator.