Most problems are caused by insufficient upkeep of the melt reservoir. If the melt reservoir is not cleaned on a regular basis, charred material will build up on the fins, reducing the heat transfer to the material. This can lead to “short shots” (incomplete over-moulds) and various blockages. If the material is left in the reservoir for days at high temperatures, it will get more viscous and eventually not flow. The melt filter must be replaced as per the maintenance guidelines. The injection nozzle and the pump seal will require replacement periodically.