There are several reasons why an LPG regulator may not fit a cylinder, some of which include:
Compatibility: LPG regulators are designed to fit specific types of cylinders. If the regulator you have is not compatible with the cylinder you are trying to use, it may not fit properly.
Thread size: The threads on the regulator and the cylinder must match in order for the regulator to fit. If the thread size is different, the regulator will not attach properly.
Damaged threads: If the threads on the cylinder or the regulator are damaged, it may prevent them from attaching properly.
Faulty regulator: If the regulator is faulty or damaged, it may not fit properly on the cylinder.
If you are experiencing difficulty fitting your LPG regulator onto a cylinder, it is recommended to check the compatibility and thread size, and to inspect the threads for any signs of damage. If you are unable to identify the issue, it is best to seek the assistance of a qualified professional to ensure proper installation and use of your LPG system