Immerse the thermostat in water and gradually heat the water.
Check the valve opening temperature.
Valve opening temperature:
88±2°C (109.4±3.6°F)
Full opening temperature: 100°C (212°F)
If the valve opening temperature is not as specified, replace the thermostat.
Check the valve lift.
Valve lift : 10 mm (0.3937 in.) or more at 100°C (212°F)
If the valve lift is not as specified, replace the thermostat.