When working with directly heated preheaters you need to be very careful in order not to burn the material. Always make sure when starting up, not to put too much material, let it melt while being mixed. Only put in a few bags at a time in order for the material to melt before adding more material. Also, don’t fill it up completely if you are not going to use everything.
Be aware of the weather forecast, because if it starts raining when you have a lot of material in the preheater then you can only keep the material in there for a little while, and if you turn off the burner and the material stiffens, then this becomes problematic.
We recommend only to fill it up when you are going to use the lot. If the weather looks like it's going to rain then only fill it to around half full or less so that you don’t end up with a lot of stiff material. If you follow this rule, then next time you are starting it up you have to turn on/off the burner manually until the mixing arms can move freely.