If your commercial stove is having temperature problems, you may be headed towards a lot of angry customers. No one wants to pay for burned bread or chicken that's only halfway cooked. So whether your oven is too hot, too cold, or not heating evenly, it's best to fix your thermostat problems as soon as you can. Luckily, if you've got a calibration issue, you can check and even fix it yourself.

Check The Thermostat's Calibration

Your oven's thermostat, when new, will have arrived with factory calibration. However, over time, it can lose calibration. To know if this has happened, you'll need an oven thermometer that you know is accurate. Set the oven to a temperature that you think it's not accurately reaching, set up your oven thermometer, and open up the bottom casing of the oven so that you can see the burner flame. This is usually as simple a removing the panel underneath the oven's door.

Watch the flame as the oven preheats. When the burner flame goes out, it means the oven thinks it has reached the target temperature. Now check your oven thermometer – does it match the temperature the oven is set to?

If the temperatures don't match, you can try recalibrating your thermostat. If they do match, you should check the placement of the capillary tube.

Calibrate The Thermostat

Be very careful, as calibrating the thermostat means working on the oven while it's turned on. Behind the thermostat knob, you will find a small screw or disc, depending on your thermostat. Turning the screw or disc will calibrate the thermostat, effectively telling it to "correct" for the temperature it's sensing.

To calibrate, turn the screw or disc in small increments until the burner comes back on. If it's unmarked, usually turning clockwise will lower the temperature if your oven is running too hot, with counterclockwise doing the reverse. Once the screw or disc is in the correct position, the burner should cycle on and off around the target temperature – keep adjusting until it does.

Check Capillary Tube Placement

The capillary tube of your thermostat is a small tube with a bulb on the end of it. The bulb is a temperature sensor, and the thermostat uses this information to adjust itself. If the bulb isn't placed correctly, even an accurate thermostat will have problems. If the temperature in your oven is fluctuating all over the place, this could very well be your problem.

The bulb is meant to clip to the inside of your oven. You should see a hole in the top of the oven cavity and then metal clips on the side near the top, and the tube will stretch between these with the bulb attached to those clips.

You need to make sure of two things: first, that the bulb is attached to the clips. If it's simply hanging loose, you should be able to clip it back in. The second thing is that, when it's clipped in, it's not in contact with the side of the oven or any metal components in the oven. If it's touching something, try to shift or rotate it away. Make sure the clips attaching the bulb haven't become bent out of shape.

If neither of these solutions fixes your problem, you may need to replace your thermostat completely. And if you noticed any damaged parts – bent clips inside the oven, for instance, or damage to the capillary tube – then replacing the damaged parts may solve all your issues. To check out replacement parts, contact a company like K & D Factory Service Inc.