it gives a great profit and market valve

If the valve is a multi turn valve, it is because the valve seat is no longer good. Replace the valve. It it is a quarter turn valve, it is because the mechanism that turns the ball is no good and the valve does not turn completely shut. once again, replace the valve.

Dear Sir,does it mean "modulating duty",it means can control the valve by a singal.

for more informaion,can refer to http://www.valve-actuator.org/Multi-turn-Valve-Actuator/118.html

1.5 or 2 inches depending on the multi-port valve that is installed. Hatawa

Go to www.CarGrus.com and download you a repair manual. Your question would require extensive knowledge and multi pages of an answer.