How to cover the mat for accelerate pre-heating?

Please use only the covers included in the mat set or permeable to heat towels or blankets of not too thick (max 1-inch layer) on top of the mat to accelerate pre-heating of the mat. 

Also, you must cover the mat completely while preheating it.

If you cover the mat only partially or put any solid objects on top of the heating mat, the temperature sensors positioned in the different layers of the mat around all the surfaces will report different and controversial measurements to the central controller. 

Finally, the controller may lose calibration and start to work incorrectly or malfunction.

If you cover the mat with non-permeable materials like a rubber, camp, or foam mat, the heating elements will gradually overheat. Finally, the overheat protection bimetals will wear off, and the mat might overheat and get broken or even catch fire.