Recently I have been called out on several service calls with complaints of the units not working properly or performing as they should. I would dare say that 80-85% of the calls are due to lack of maintenance. And, I would dare say nearly all of the remaining calls are due to improperly loaded of the units such as the one pictured here.
I remind my clients continually that proper air flow is essential for proper operation of each merchandiser. It has become apparent this is something that needs to be addressed as it appears most retailers are unaware of the limitations of their units.
Besides allowing better cooling of the product, proper air flow increases the longevity of the refrigeration components and reduces the cost of operation via energy loss. You see if the compressor is constantly running and trying to satisfy but is unable – it will never shut off. Obviously if the compressor never shuts off we are losing energy running the unit, creating excess heat internally, and breaking down the oil inside the compressor. And, once the oil breaks down it no longer lubricates the components as it should thus causing failure.
Keep in mind, in most circumstances, the evaporator fans (see below for visual) are return air fans and not cooling fans – by definition. In other words, these fans are sucking air in and NOT blowing it out. The evaporator fans actually draw return air into the evaporator area over the evaporator coil (where the heat exchange takes place) and then discharges the cold air down the back side of the unit.
In most cases, the shelving or merchandisers either has an “air gap” or a “stand-off” (see above for visual) in the back of the cabinet to prevent the product from blocking the critical air flow passageway. And, this is where the trouble begins…. Many of my customers completely and totally overstock their units thus blocking the air flow passage. When blocking the air flow passage, this ultimately creates a poor circulation problem which can create numerous problems within the operation of the merchandiser.
One of the problems created by improper air flow occurs when the top shelf is cold and maintaining proper temperature while the lower and lower most shelves end up being 20-40*F warmer than the top shelf.
Another problem is where the evaporator coil ices up. The worst case scenario is where the compressor never shuts off and fails. No matter which symptom first appears, the ultimate result is usually compressor failure.
I have attached pictures of one of my clients who has taken my recommendation seriously. The following pictures are a perfect example of how to properly stock a display cooler or freezer. These pictures are from Barden’s Market in South Haven, Michigan (See Below). Please note the care taken to ensure “aisle ways” were created in between products as well as an air cap in between the shelves (height-wise). The way this unit is stocked shows how easily air flow can cool the product equally and freely without any sort of blockage. As a customer, I appreciate how appealing a neat and organized retailer looks rather than that overstocked, jam full packed unit looks. I also have appreciate how much more user friendly it is having a unit that is not overstuffed in order to pull product from it. I have actually witness customers pulling a particular product from a freezer while 2 or 3 other products fell out at the same time as there simply was no clearance or space in between products.