Walk-in coolers and freezers are sizable investments for any foodservice facility. If not properly maintained, they can become an expensive maintenance hassle. Here are a few items to be aware of to reduce operating and maintenance costs, as well as improve reliability.
One of the most important maintenance items is keeping the condenser coil clean. The condenser is usually located outdoors with the compressor. If air cannot pass through the finned coil surface, the high side pressure will increase causing the system to lose cooling capacity and consume more electricity. When there is enough blockage of the coil surface, the system will stop working completely when the high-pressure safety switch trips. Sometimes the switch will reset by itself, other times it will require a service technician to reset the switch and determine the cause.
In addition to higher operating pressures, there will also be excessive heat build-up in the compressor. Running at elevated temperatures can shorten the life of the compressor. If the temperature of the compressor gets too high, the internal overload switch will be activated inside the compressor. This too will stop the compressor. Eventually, the internal switch will reset, but repeated overloads can cause compressor failure.
Depending on where the condenser is located, it could require cleaning anywhere from monthly to yearly. On rare occasions, walk-in cooler and freezer units use water-cooled condensers. These condensers require less maintenance but are more specialized and should be serviced by technicians.
The evaporator coil is the fan unit inside the walk-in cooler or freezer. Just like the condenser coil, the evaporator coil needs to be sufficiently clean to operate at full capacity and efficiency. Usually, the inside of a cooler or freezer are kept very clean and the coil does not need to be cleaned nearly as often as the condenser coil. On walk-in coolers, annual cleanings are usually enough.
Walk-in freezers coils, however, are subject to ice build-up. The ice can form from not enough defrost cycles, too short of defrost cycles, defective door gaskets, and/or excessive door openings. If ice remains on part of the evaporator coil after a defrost cycle, the evaporator coil will not operate at full capacity. This will cause longer compressor run times and higher electrical usage. To see if there is ice build-up, you need to look at the backside of the evaporator coil. If you see ice, wait a day or two to see if it clears with additional defrost cycles. If it doesn’t, it’s time to call your refrigeration technician to make some adjustments to the defrost cycle.
Keeping the door gaskets in good shape will prevent temperature problems and excessive compressor run times. More importantly, door gaskets that don’t seal properly, or missing door gaskets will cause ice build-up on the evaporator coil. Continuous frost load on the evaporator coil could exceed the defrosting ability of the evaporator coil. Once the coil is fully coated with frost and ice, airflow will be blocked, and the freezer will not be able to maintain temperature.
Taking care of these three items will improve the performance of your refrigeration system, reduce unnecessary emergency service calls, reduce electricity usage, and prolong the life of your refrigeration unit.