Second hand storage heaters need to be VERY carefully checked before installing them. Both electrically and for the type and condition of the thermal insulation which is invariably damaged during dis-assembly and removal.
If the thermostat has failed and the fusible link has been replaced by a bit of brass then they can and have become so hot the wall behind has been scorched.
The bricks get so hot in normal operation that with defective insulation the casing can ( and has ) got hot enough to scorch the wall behind or burn anyone touching the casing
