A walk-in cooler that will not hold temperature usually has one of five problems. The door is letting in warm air, airflow in the box is blocked, the condenser coil is dirty, the evaporator has iced over, or a part such as a fan motor has failed. Staff can check the first three in a few minutes. The last two need a technician.
Infinity Heating and Cooling repairs and maintains walk-in coolers and freezers for restaurants, grocery stores, hotels, and other businesses in the Las Vegas Valley. This guide deals with the food first and then works through the symptoms one at a time.
Protect the food first
Cold food that needs temperature control has to stay at 41°F or colder under Southern Nevada Health District rules. The district lists broken refrigeration among its examples of an imminent health hazard. When one occurs, the operator must stop food handling in the affected area and notify the Health District. Take these steps before any troubleshooting:
- Read the product temperature with a probe thermometer. The wall display shows air temperature, which can differ from the temperature of the food.
- Keep the door shut, and log the time and each reading.
- Move food that needs temperature control to another working cooler, or pack it in ice.
- Call your refrigeration contractor. Call SNHD as well if you cannot keep the food at 41°F or colder.
SNHD’s guidance for power outages says food between 42°F and 45°F must be used within 24 hours, and food above 45°F must be used within four hours or discarded. Ask your inspector how the district applies those limits to an equipment failure.
What each symptom tells you
The temperature climbs during service and recovers overnight
This pattern points to warm air and heavy use, not to a failed part. Check the door first. Foodservice Equipment & Supplies magazine notes that a gasket that fails to seal lets in moisture, which can freeze the evaporator coil, and that a sagging door lets in outside air. Look for torn or stiff gaskets, a torn door sweep, a closer that no longer pulls the door shut, and missing strip curtains.
Then look at how the box is loaded. Heatcraft’s installation manual for unit coolers says the air pattern must cover the entire room, and it warns against stacking product in front of the fans. Large batches of hot food placed in the cooler add to the load as well.
The fans run and the coil is clear, but the box stays warm
Go to the condensing unit, which is often on the roof or behind the building. A coil matted with dust or kitchen grease cannot reject heat, and the system loses capacity as the outdoor temperature rises. ENERGY STAR reports that basic condenser coil cleaning cut energy use by an average of 17 percent across ten units it reviewed.
If the coil is clean, the system may be low on refrigerant. Heatcraft’s manual tells technicians to leak test all connections when a system appears to need more refrigerant. A leak is found and repaired through commercial refrigeration repair in Las Vegas.
The evaporator coil is covered in ice
A coil packed with frost blocks its own airflow, so the box warms even while the compressor runs. The usual causes are a door leak, a failed defrost heater, a fault in the defrost timer or control, and a frozen drain line. Heatcraft’s manual lists a burned-out defrost heater and a frozen drain line among its defrost faults.
Do not chip the ice off with a tool, because the coil tubing and fins puncture easily. Shut the unit down to melt the ice only after the food has been moved, and have the cause found before you restart.
The evaporator fans are not turning
A fan motor may have failed or tripped on thermal overload, or ice may have jammed a blade. On some systems a fan delay control holds the fans off until the coil is cold, so a short pause after a defrost cycle is normal.
The condensing unit is silent or starts and stops
Check the breaker and the disconnect once. If the unit still will not run, or starts and stops every few minutes, leave it off and call for service, because repeated restarts can damage the compressor. Likely causes include a failed contactor or capacitor, a tripped pressure control, and a compressor fault.
Why it happens more often in a Las Vegas summer
A rooftop condensing unit works against the outdoor air temperature. On a 110-degree afternoon it has far less margin than it has in March, so a coil that was slightly dirty in spring can push the system past its limit in July. Our article on why AC units fail first in Las Vegas heat waves describes the same effect on rooftop air conditioning.
What staff can do and what needs a technician
Kitchen staff can handle these tasks:
- Wipe door gaskets with soap and water and report any that are torn
- Keep product clear of the evaporator fans
- Clear boxes and trash from around the condensing unit
- Confirm the setpoint and log temperatures every shift
Leave these to a technician:
- Coil cleaning with chemicals
- Tests on defrost heaters, timers, and fan motors
- Refrigerant leak repair and charging, which federal rules restrict to EPA-certified technicians
- Electrical checks at the condensing unit
How to keep it from happening again
ENERGY STAR recommends six-month service intervals for the evaporators and condensers on walk-ins, with electrical and mechanical testing and hardware adjustments at the same visits. FE&S adds a yearly check that drain lines are clear and electrical connections are tight.
Infinity recommends the same six-month schedule for ice machine service, which protects ice quality and prevents mineral buildup.
Repair or replace
FE&S lists the signs that a walk-in is near the end of its service life. The unit can no longer maintain proper temperatures, the doors do not seal and the box is more than 10 years old, or the floors and panels have deteriorated.
Frequently asked questions
1) What temperature should a walk-in cooler be set to?
Food that needs temperature control must be held at 41°F or colder. Many operators set the box a few degrees below that, commonly 35°F to 38°F, to allow for door openings. A much lower setting overworks the unit and can freeze produce.
2) Why does my walk-in cooler keep freezing up?
Ice on the evaporator usually comes from moist air entering at a leaking door or from a defrost fault, such as a failed heater or timer.
3) How often should a walk-in cooler be serviced?
Twice a year is the interval ENERGY STAR gives for cleaning the coils on a walk-in. Units that sit outdoors or draw in kitchen grease may need it more often.
4) Can I add refrigerant to a walk-in cooler myself?
No. Refrigerant work is restricted to EPA-certified technicians, and a system that is low has a leak that must be found first.
5) Is it a problem if my walk-in cooler runs all the time?
Long run times are normal on hot afternoons. A unit that never cycles off, even overnight, is short on capacity.
Conclusion
Start with the door, the loading, and the condenser coil, since those are the faults staff can correct. Ice on the coil, fans that will not turn, or a unit that will not run call for a technician the same day.
For walk-in cooler repair in Las Vegas, request refrigeration service from Infinity Heating and Cooling. The office line is (702) 291-2000.
