First, the tank is removed from the vehicle for inspection where we check the tank for damage and check the valves in the tank for safety and operation. If there is gas still left in the tank, it must be fully purged before it can be properly inspected.
The safety valve is always changed during a tank test as its function is to vent gas out of the tank if the pressure ever happens to build-up to a high level so it is very important to change the safety valve to make sure it operates correctly.
The lock-off and sender units are also tested, the valves are re-installed and all threads are once again sealed. All seals and retaining screws are to be replaced.
If it’s an automotive gas cylinder, the cylinder will then be re-fitted and connected with the LPG system in the vehicle.