Immerse the thermostat in water and gradually heat the water.
Check the valve opening temperature.
Valve opening temperature : 88 ± 1.5°C (190.4 ± 2.7˚F)
Full opening temperature : 100°C (212˚F)
Check the valve lift.
Valve lift : 8 mm (0.3 in) or more at 95°C (203˚F)