Maintaining consistent temperatures is one of the most critical functions of any commercial refrigeration unit, but it's particularly essential for walk-in freezers. Inconsistent temperatures in your freezer can threaten the health and safety of your establishment and potentially result in spoilage that can disrupt your operations or require expensive replacements.
You'll likely notice inconsistent temperatures if your freezer keeps shutting off before completing a cycle. Even if your freezer is currently keeping temperatures below freezing, short cycling leaves your system dangerously close to being unable to maintain those temperatures for long. Fortunately, short cycles often result from one of these three common and repairable issues.
1. Faulty Condenser Fan
Unlike residential air conditioning units, most rooftop commercial refrigeration units will have multiple condenser fans. However, these fans serve the same purpose as the condenser fans in any other HVACR system. When your freezer's compressor is running, the fans help release heat from the refrigerant in the condenser coils and keep the compressor cool.
Even a single faulty fan can drastically impact system efficiency and cause the compressor to overheat, especially on hot days or when there's a heavy load on the freezer. Although your freezer may still run, the compressor will short cycle due to the overload protection tripping. Frequent overloads can damage your compressor, so a faulty condenser fan is a serious issue that requires immediate attention.
2. Refrigerant Leaks
Refrigerant leaks are a potential issue in any HVACR system. These systems require refrigerant to transport heat from one area (your freezer) to another (the outside environment). Because of the nature of refrigerant chemicals, HVACR requires precise internal pressures to operate efficiently and reliably. Any loss of refrigerant can have a substantial impact on system behavior.
Oddly enough, low refrigerant pressure can potentially result in colder temperatures at your freezer's evaporator. This situation can result in more frequent and severe icing, potentially preventing the system's defrost cycle from fully clearing the evaporator. As the problem worsens, the ice will insulate the evaporator coil and ultimately cause the compressor to short cycle.
3. Electric Defrost Issues
Commercial freezers require a defrost system to keep the evaporator coils and suction line from icing up. Due to the low temperatures in a walk-in freezer, ice will inevitably form on the coils as humidity condenses from the surrounding air. Unfortunately, ice is a highly effective insulator, and sufficient ice build-up will prevent the evaporator from absorbing more heat from the freezer box.
Most modern systems use an electric defrost timer and a small heater to remove ice from the coils. Problems with any part of the defrost system can allow ice to accumulate to dangerous levels, eventually causing the compressor to overheat and trigger its overload protection. If you notice a lot of ice on your evaporator, a defrost issue may be the underlying cause of your system's short cycling.
For more information on refrigeration, contact a professional near you.