If a hot runner manifold or drop is

If a hot runner manifold or drop is leaking material there will be a trap area for material to collect in and degrade. These leaks can allow trapped degraded material to contaminate the melt stream and create brown streaks. Unfortunately, the mold must be pulled to examine the hot runner manifold if there are suspected leaks. One sign of a hot runner leak can be when the process is losing cushion; if the process is losing cushion the plastic is going somewhere, either leaking at the nozzle, leaking past the non-return valve, or leaking in the hot runner manifold. Running a mold with a hot runner leak will eventually lead to failure of heater zones and require a great deal of work to repair.