The installation of the evaporator coil is vital to the proper operation of the entire refrigeration system when you’re installing a walk-in cooler or freezer.

Several general guidelines apply to most installations; however, it is always best to check with the manufacturer of the evaporator for specific instructions.

This article offers some general guidelines.

  • The air pattern of the evaporator must envelop the entire room. This is important in order to provide a more uniform temperature throughout the entire box. Do not install the coil where product could potentially be stacked and block the airflow.

    Always allow for sufficient space between the rear and sides of the evaporator and the wall to permit free return air. Check with the manufacturer of the particular coil for exact minimum spacing requirements.

  • Never install an evaporator above a door. Placing an evaporator above a door can cause the evaporator to draw warm, humid air through the coil each time the door is opened. This, in turn, will cause the evaporators to frost up more quickly and may cause icing problems.

  • Do not install an evaporator coil in an area where it will interfere with the cooler’s aisles or storage racks. This may cause a problem for the owner, which could result in the evaporator needing to be relocated. The location of the evaporator should allow for easy storage and removal of the refrigerated product.

  • The evaporator should be installed in a location that will provide the shortest possible distance between it and the condensing unit. Excessive piping can increase the pressure drop between the evaporator and the condensing unit. Excessive pressure drop will decrease the system’s overall refrigeration capacity.

  • The location of the condensate drains should provide for minimum pipe length. This will allow for proper drainage. In addition, the unit should be kept level for proper drainage and should be trapped.

    When draining two or more evaporators in a common drain, always trap drain lines individually to prevent vapor migration. On low-temperature evaporators, the traps should be located outside the case.

    If freezing of the traps is still a potential problem, they should be heated and wrapped.

  • Make sure supports for hanging the unit are strong enough to hold its weight. For coils up to 250 lb, 5/16-in. bolts or threaded rods should be sufficient. For coils up to 500 lb, 3/8-in. bolts or threaded rods should be used. Coils over 500 lb should use 5/8-in. bolts or threaded rods.

  • Comply with NSF Standard No. 7. When using rod hangers, allow adequate space between the top of the unit and the ceiling for cleaning. If you are fastening the evaporator flush to the top of the cooler, seal the joint between the top and ceiling with an approved sealant.

    Before installing any evaporator coil, it is important to consider all the necessary installation requirements. It is always easiest to make changes before actually installing the coil. Once the coil is installed, changes will be time consuming and costly to you, the installing contractor.

    Marchese is owner of Arctic-Air Refrigeration, Pittsburgh, PA. He can be reached at P.O. Box 97022, Pittsburgh, PA 15229; 412-734-4433.

    Publication date: 02/11/2002