Thank you for the site. However, i found an error in the description of
how an Thermal Expansion Valve operates in the site ; the text says :
'In an expansion valve air conditioning system, refrigerant flow to the
evaporator varies according to the pressure in the suction line
(evaporator outlet). This is detected by a sensing bulb mounted on the
line, and relayed to the expansion valve via a capillary tube
'

The refrigerant flow to the evaporator is varied NOT according to the
pressure in the suction line , but rather is it based on the pipe
surface TEMPERATURE as sensed at the outlet of the evaporator (suction
line) by the sensing bulb that is strapped in close contact to the
suction line. Its purpose is to maintain a certain superheat value
(typically 8-12 degrees f.) so all of the liquid refrigerant is
evaporated as it makes it journey thru the evaporator as well as picking
up additional heat (superheat) to ensure that only vapor refrigerant
exits the evaporator... as a compressor is only designed to pump 100%
vapor to avoid possible damage.