Abstract: An assembly is used for chemical injection through a wellhead to a capillary line in a well. A capillary hanger installs in the wellhead to support the capillary line. A no-return valve of the capillary hanger prevents fluid communication uphole from the supported capillary line. An injection module mounts above a gate valve on the wellhead and includes a movable mandrel disposed therein. Hydraulic pressure applied to a piston chamber in the module extends the mandrel through the open gate valve so that a distal end of the mandrel can open the no-return valve. At this point, chemical injection introduced into the module can communicate through a flow bore of the extended mandrel, through the open non-return valve, and on through the supported capillary line in the well.