Installation and usage requirements: 1) welded pipe expansion valve with the system pipe welding, we must pay attention to the following points; 1.1, use a damp cloth or a wet cotton bag to protect bodyon the body, To avoid high that temperature burn in the valve parts in welding. Please note that the 1.2 welding torch flame direction toward the body outward. 1.3 low temperature silverelectrode welding. 2) expansion valve maintenance should be designated professional staff.