Refrigerator thermostat

I have a cold plate reefer/freezer. The reefer gets it's cold air using a muffin fan that blows air from the freezer when the thermostat calls for it. The old thermostat went out so I replaced it with a new one. It has a long SS capillary tube that I ran into the reefer in the same place as the old one.

The problem is that I can't seem to find a good spot on the thermostat. It basically acts like an on-off switch. If I set it where it turns the fan on, it won't turn off. When I back it off a bit to turn the fan on, it won't turn back on again, at least not in an acceptable range.

Does the amount of that ss tube in the reefer matter? I was thinking thermocouple, where only the tip measures the temperature, so I left the excess tubing outside of the reefer, next to the thermostat. However, I remembered that the one I removed had most of the tubing coiled up inside the reefer. Is that they way they're supposed to be installed?

Keith wrote:

However, I remembered that the one I removed had most of the tubing coiled up inside the reefer. Is that they way they're supposed to be installed?

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To give you a definitive answer you really do need to provided the make and model of the thermostat. Some have a fixed "span" of a few degrees and others are adjustable over a huge range either side of the set point. Changing the setpoint alone may just move the upper or lower span limits out of range of the* machine.

In the meantime ...

It really doesn't matter where the excess capillary is located as long as it is not kinked. If it was all inside the box then replace it the same way.

Make sure the capillary or sensor bulb is not touching the cold plate or the sides of the box. It needs to detect the air temperature, not the box or its contents. Make sure air flow around the bulb or tube is not blocked.