Oven thermometers closely resemble their cold readout counterparts. They can either sit or hang from the rack, and they can display temperatures using a dial or rising liquid. The only difference is the temperature range is higher to accommodate the hot cavity temperature. The ideal placement for an oven thermometer is in the back of the cavity, near the built-in thermostat. This will let you know whether or not the thermostat is functioning properly and the knob is properly calibrated. If the readings are not matching up, you can pull off the knob and adjust the dial on the back a few degrees to account for any discrepancy. Having the thermometer in the back of the oven cavity does have a decided disadvantage, especially if the interior is not lit. Employees will have to leave the door open a bit longer in order to peer all the way in the back and see the temperature, and the longer the door is open, the more heat will escape. It is important that you keep the thermometer face clean so a reading can be taken as quickly as possible.