Why Is My Reach-In Refrigerator Freezing Food?

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Updated October 14, 2026

Check the set point and the thermometer

Staff sometimes turn the dial colder on a busy day and never turn it back. Compare the controller reading with a calibrated thermometer in a glass of water in the middle shelf. A gap of more than 2 to 3°F means the sensor or thermostat is off.

Where the cold air lands

Cold air leaves the evaporator fan at well below the cabinet temperature. Lettuce, herbs and dairy placed directly in front of the fan cover freeze even when the cabinet averages 37°F. Keep delicate product on the door side and away from the top-rear corner.

Causes a technician fixes

• Thermostat stuck closed or a mechanical thermostat that has drifted: the compressor never cycles off.
• Failed temperature probe on electronic controllers: reads warmer than reality, so the unit keeps running.
• Stuck relay or contactor: power to the compressor never drops.
• Wrong replacement part: a thermostat with a freezer range fitted to a cooler.

Why it matters beyond waste

A unit that never cycles off also never defrosts properly on off-cycle designs, so the evaporator ices up and the cabinet then warms. Freezing today often becomes "not cooling" next week. See commercial refrigerator not cooling.

How to check whether the thermostat is at fault

1. Put a calibrated thermometer in a glass of water on the middle shelf and leave it for an hour.
2. Compare the reading with the set point and the display.
3. Watch whether the compressor ever shuts off. In a healthy unit it cycles off within an hour or so once the cabinet reaches set point, depending on door traffic.
4. Raise the set point by 2°F and check the water glass again after a few hours.

If the cabinet keeps dropping no matter where you set it, the control is not shutting the compressor off. That is a technician repair, because the cause can be the control, the probe, a relay or a contactor.

Mechanical vs electronic controls

Older reach-ins use a mechanical thermostat with a sensing bulb clipped near the evaporator. If that bulb falls off its clip or gets moved during cleaning, the thermostat reads the wrong spot and can run the cabinet too cold. Newer units use an electronic controller with one or more probes. Probes can fail, get loose, or get buried in ice. Either way, the fix starts with finding what the control is actually sensing.

Product that freezes most easily

• Leafy greens and herbs
• Soft cheeses and dairy
• Sauces and dressings in thin containers
• Cut fruit
• Eggs

Store these on the door side or upper front shelves, away from the evaporator outlet. Heavy, dense product such as cased drinks and raw proteins in deep containers is less sensitive and can sit closer to the fan.

Freezers that run too cold

A freezer that runs much colder than set point wastes energy and can overwork the compressor, but it rarely harms frozen food. The same stuck-control causes apply, and it is worth fixing before the compressor wears out.

What the technician does on this call

1. Measures cabinet and product temperatures against the set point and display.
2. Checks where the thermostat bulb or controller probe sits and whether it is secure.
3. Tests the control for continuity at different temperatures to see whether it opens.
4. Checks the relay or contactor feeding the compressor for welded contacts.
5. Looks at the evaporator for ice that a never-ending run cycle has built up.
6. Replaces the failed part and confirms the unit cycles normally over a full run.

Food safety when product freezes

Freezing is a quality problem more than a safety problem for most foods: frozen lettuce wilts, emulsions break, eggs crack. Throw out product whose quality is ruined. Frozen product that has thawed in the cooler can usually be used if it stayed at 41°F or below, but follow your food safety plan.

Related problems

• Uneven temperatures: a unit can freeze at the back and run warm at the front at the same time.
• Frost and ice: constant running stops off-cycle defrost.
• Repair cost: thermostats and probes are among the lower-cost repairs.

Bay Area factors

Freezing complaints cluster in two situations here. In coastal San Francisco and Peninsula kitchens with cool, humid air, units run less and staff often turn the dial colder "to be safe". In hot South Bay and East Bay kitchens in summer, a unit that struggled all afternoon may overshoot at night once the room cools. Logging cabinet temperature morning and evening shows which pattern you have.

Local environmental health departments (Santa Clara County Department of Environmental Health, San Mateo County Environmental Health, Alameda County Environmental Health and San Francisco Department of Public Health) enforce the California Retail Food Code. Inspectors probe food, not just air, and a cold-holding violation is one of the most common findings.

Frequently asked questions

Sources

• FDA Food Code 2022
• KaTom: True refrigerator troubleshooting guide

Published by Cool Aid Air Conditioning & Refrigeration, a family business serving the Bay Area since 1966. Owner Jim McKinny holds California C-20 and C-38 contractor licenses and EPA Universal certification. Repairs we complete carry our 1-year parts & labor warranty.