If you want to test a thermostat on an electric water heater, you will also need to check the heating element. This is important, especially as open and grounded heating elements result in inaccurate tests.
1.Move to the thermostat terminals and check if it is supplied with power. If it is, you will have a reading of 240V on terminals 1 and 3. But if there is no reading, check its power source. Also, check for current on the high limit switch.
2.Disable the lower thermostat by rotating its dial to the least setting. Next, turn up the temperature of the upper thermostat to look for faults.
3.Place the prongs of the multimeter on the terminal 1 and blue wire of the heating element. This will help you detect if power is supplied between the upper heating element and blue wire.
4.If the tool reads 240V that means there is power on the setup. Next place the prongs on terminal 2 and the blue wire of the heating element. But if there are no readings that means the thermostat is faulty.
5. Muévase al termostato inferior del calentador. Ajuste el dial del termostato superior al nivel mínimo mientras configura el otro termostato al nivel más alto.
6. Vuelva al terminal 1 y al cable rojo del elemento calefactor inferior. Coloque una sonda en ambos para detectar energía. Si lee 240V, entonces hay energía en la configuración.
7.Coloque las sondas en el terminal 2 y el cable rojo del elemento calefactor inferior. Si no tiene lecturas, deberá cambiar el termostato por uno nuevo.