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HVAC School - For Techs, By Techs


Feb 14, 2018

In today's podcast episode, Eric Mele comes on to talk about reach-in coolers (refrigerators), freezers, and wine coolers with some mindset and technical tips. We mostly discuss self-contained equipment.

Coolers are medium-temperature applications, while freezers are low-temperature applications. Wine coolers vary from normal coolers because they have slightly higher temperatures and controlled humidity. The cooler must control humidity to preserve the wine quality and prevent the cork from swelling.

Metering devices vary with the size and type of equipment. We typically see capillary tubes in smaller reach-in coolers and TXV in larger ones and blast chillers. We typically use automatic expansion valves (AEVs/AXVs) for wine coolers. An AEV controls suction pressure in conjunction with a TXV, which controls superheat.

Hooking up gauges is typically a last resort. We can chalk up most reach-in cooler problems to restrictions, which usually indicate cleanliness issues that are easy to solve. For example, dirty condenser coils can cause cap tube restrictions.

Control strategies vary by size, application, and complexity. For example, simple reach-ins rely on manual defrost only. However, even higher-end blast-chillers recommend manual de-icing (although they DO have defrost controls). The main defrost types are manual, fan, and electric. Smaller reach-ins have a "cold control." Cold controls are relatively simple dials that stop the compressor when the evaporator coil reaches a set temperature.

Most reach-in refrigerators are ONLY intended to hold products at temperature. With the exception of blast chillers, most reach-ins cannot bring a bunch of hot food down to temperature. These situations will result in poor performance, so customers should be aware of the refrigerator's appropriate usage.

Eric also discusses:

  • The troubles of charging reach-in cases
  • Creating your own access ports
  • Electric defrost in reach-in applications
  • Thermal imaging cameras in diagnosis
  • Manual defrost strategies
  • Pump down
 

Check out Eric Mele on YouTube HERE.

If you have an iPhone, subscribe to the podcast HERE, and if you have an Android phone, subscribe HERE.