1. Locate release valve Fig.4. on right hand side of press. See Fig.4.Remove tubing from the valve. If head now opens the problem is either with improper adjustment of the release valve actuating mechanism or a bad valve. Make sure that rod fully depresses the valve plunger. Test press after any adjustment. If after testing press the head still does not open the release valve is bad. Replace or repair.
2. A defective high pressure valve. Replace or repair. For repair see Section Fig.4.
3. Presses with electric timer release. If after checking steps 1&2, the head does not open the fault is with the timer. Remove tube and fitting from release valve solenoid. See Fig.4, if machine now opens have on electrician check the wiring and components as shown on electrical diagrams Replace any defective items and test press.