All evaporator coils mounted in walk in coolers and freezers have a drain connection on the bottom. The fitting size of this connection varies by the style of the coil. The excess condensation that forms on the cold surfaces inside the coil cabinet must be carried away from the refrigerated space; health codes prevent the drainage of this condensation within the walk in cooler itself. Drain lines in walk in freezers must run through copper and should be wrapped with heat tape. Drain lines in walk in coolers can usually run through PVC drainage material. All drain lines should be properly pitched and trapped. For ease of maintenance in the future, unions should be provided at the coils.
In most cases, local codes will dictate the ultimate destination for this drain line. If you are still in the planning stages for the building itself, a floor drain can be added to the construction. It should be placed against the exterior of the walk in cooler or freezer wall. The exact placement will be determined by the individual design of the walk in cooler and floor plan of the business. We can suggest ideal placements once we have the proper information in our hands.
For an existing structure, you will usually have to work with the available opportunities at the site. If no floor drain is available, perhaps there is a sink that can be used. A plumber or your refrigeration contractor could provide additional advice concerning this decision.
In the next entry, I will explain what to do if the drainage system malfunctions… stay tuned!