Power off, the regulator still need about 10-20 minutes to release the inner pressure. If the bubble stops in 20 minutes after power off, the regulator is no problem.2. According the coil solenoid feature, if the bubbles rate less than 1 bubble per 3 seconds, we can take it is qulified.3. 20 minutes later after power off, If bubble rate over  1 bubble per 3 seconds, please check the following steps:    3.1 Solenoid Coil  checking: if power on/off, can not hear a click sound, the problem on the solenoid coil. we can open the solenoid coil cover to check whether the cable is loosen.  3.2 If you can get the click sound when power on/off, the problem on the spring part.When power off, the spring push the bar(part A) close the hole, so the gas be cut off.  - Clean the bar(part A) surface and the hole B, maybe dirty between them.- You can slightly  stretch the spring to increase the spring power.4. if problem can not be resolved, you can contact us for further assistance