How you will check thermostatic expansion valve is working or not

Open the flare nut from liquid line solenoid valve or drier filter. Remove the txv sensing bulb from suction line . Take some ice cubes in a small container and the sensing bulb dip in the ice cube container. Connect a gauge manifold in suction line and put some pressure in cooling coil then we check the gas coming or not where we open the flare nut. If the txv is good condition the gas should not come in the liquid line. Then removed the txv sensing bulb from the ice container and heat up by our fingers then the gas should come from the liquid line where we opened the flare nut. This is 1 method of checking txv . You can try the same procedure from liquid line to suction line. If we dip the txv sensing bulb in the ice container the txv should be close. Then we removed the sensing bulb from ice container and heat up the sensing bulb by gingers that time txv should be open. That all . Everyone's checking methods are different. Above mentioned procedures are brazed type txv. If open type(flange or flare ) txv you can directly see the valve seating is closing and opening when you dip or remove the sensing bulb in ice container.