If your walk-in cooler isn’t holding temperature, the most likely causes are a damaged door gasket letting warm air in, a frosted-over evaporator coil blocking airflow, or a refrigeration system issue such as low refrigerant or a failing compressor. The first two are things a manager can check right now. The second two require a licensed refrigeration technician.
Start Here: Checks You Can Do Before Calling for Service
Before calling a technician, a few quick checks can either solve the problem or give the service tech better information when they arrive. These checks are safe for any manager or kitchen supervisor to perform:
- Door gaskets: Run your hand along the perimeter of every door on the cooler. Gaskets should form a tight seal with no gaps, cracks, or sections that have pulled away from the frame. A failed gasket is one of the most common causes of temperature loss in walk-in coolers and is often visible to the eye. Replacements are inexpensive and can be installed quickly.
- Door closers and latches: Check that every door closes fully and latches securely. A door that doesn’t close completely due to a worn hinge or misaligned latch is functionally the same as an open door.
- Evaporator coils: Look at the evaporator unit inside the cooler. If you see a solid block of ice where the coil should be, the coil has frosted over and air cannot circulate. This is called a defrost failure. The cooler will warm up even though the refrigeration system is technically running. Do not chip the ice. The defrost system needs to be diagnosed and repaired.
- Airflow inside the box: Check whether product is stacked directly against or in front of the evaporator unit. Blocked airflow prevents cold air from circulating through the cooler. Rearrange product to maintain at least 6 inches of clearance around the unit.
- Thermostat setting: Confirm the thermostat setpoint hasn’t been changed. On True and Hoshizaki reach-ins and walk-ins, digital controllers can sometimes lose settings after a power interruption. A walk-in should hold between 35 and 38 degrees Fahrenheit for most food storage applications.
- Condenser unit: If your condenser is located outside or on the roof, check whether it’s visibly obstructed by debris, leaves, or snow. A blocked condenser cannot shed heat and will cause the system to run poorly or shut down.
Signs It’s a Refrigeration System Problem
If the checks above don’t reveal an obvious problem, the issue is likely inside the refrigeration system itself. These situations require a licensed technician:
- Low refrigerant charge: If refrigerant has leaked, the system loses capacity. The evaporator may ice over at the inlet but not the outlet, or run without producing adequate cooling. You cannot add refrigerant yourself. Only EPA Section 608-certified technicians can handle refrigerants legally.
- Compressor failure: A failing compressor may still run but not maintain adequate pressure differential. Listen for unusual noise from the condensing unit, such as hard starts, rattling, or the unit cycling on and off rapidly. A compressor that trips its overload repeatedly is telling you something is wrong.
- Expansion valve failure: The TXV or electronic expansion valve meters refrigerant into the evaporator. When it fails or sticks, cooling capacity drops or the evaporator ices up abnormally.
- Defrost board or timer failure: If your evaporator ices over on a regular cycle, the defrost system isn’t completing its cycles correctly. This is typically a control board, timer, or defrost heater issue depending on the equipment model.
How SAMCO FM Diagnoses Walk-In Cooler Problems
When a SAMCO FM technician arrives on site, they start with a full system evaluation before recommending repairs. This includes measuring supply and return air temperatures inside the box, checking refrigerant pressures at the high and low side, inspecting the evaporator and condenser coils, testing the defrost cycle, and checking electrical components including contactors and capacitors at the condensing unit.
We work on True and Hoshizaki walk-in systems along with equipment from most other manufacturers. Our technicians carry common repair parts on their service vehicles to minimize wait time.
SAMCO FM serves restaurants, grocery stores, convenience stores, food distributors, and institutional kitchens across Metro Detroit. We’ve been doing commercial refrigeration service in Southeast Michigan since 1997, and our team brings 90+ years of combined experience to every service call.
When to Call a Professional
If your walk-in cooler temperature is rising and you can’t identify an obvious cause, call SAMCO FM before product temperatures reach 41 degrees Fahrenheit, the Michigan Department of Agriculture and Rural Development threshold for food safety violations. A walk-in temperature failure can result in thousands of dollars in spoiled food and potential regulatory action.
SAMCO FM offers 24/7 emergency service for commercial refrigeration failures in Wayne, Oakland, Macomb, and Washtenaw counties. Call (734) 838-6300, email service@samcofm.com, or submit a service request at samcofm.com. We prioritize food safety emergencies and will tell you our estimated response time when you call.
Frequently Asked Questions
How cold should a walk-in cooler be?
Walk-in coolers for food service should hold between 35 and 38 degrees Fahrenheit for most perishable items. Michigan food code requires that cold food be held at 41 degrees Fahrenheit or below. A walk-in running at 42 to 45 degrees is a code violation and a food safety risk, even if it feels cold when you open the door.
How long can food stay safe if my walk-in cooler fails?
A walk-in cooler that holds its temperature initially when the refrigeration system fails can remain below 41 degrees for a few hours depending on how well it’s insulated, how full it is, and the ambient temperature. However, you should not assume product is safe after more than 2 to 4 hours above 41 degrees without temperature documentation. When in doubt, call your health department and SAMCO FM at the same time.
Why does my walk-in cooler ice up inside?
Ice buildup inside a walk-in cooler almost always points to a defrost system failure. The defrost cycle runs periodically to melt frost off the evaporator coils so airflow is maintained. When defrost stops working, frost accumulates into a solid block of ice, airflow stops, and the cooler warms up. The defrost heater, termination thermostat, defrost timer, or control board are the usual culprits, depending on the unit’s age and design.
Can I repair a walk-in cooler door gasket myself?
Yes, in most cases. Walk-in door gaskets are typically held in place by a snap-in channel around the door perimeter. Replacement gaskets are available from commercial refrigeration suppliers and can be installed by anyone comfortable with basic maintenance. Make sure to match the gasket profile to your door model. If the door frame is warped or the door closer is misaligned, a gasket replacement alone won’t solve the problem.
