Master Controller

Interested in a system that increases food safety, prevents product loss and saves significantly on your energy bill?

Maintaining proper, consistent temperature in a walk-in or merchandiser is vital for protecting perishable items. However, when evaporator coils are blocked due to ice build-up, they lose the ability to transfer heat properly. Temperatures in a refrigerated space can then rise, resulting in spoilage.

The Master Controller system is an electronic controller for Master-Bilt walk-in cooler and freezer refrigeration systems. It is standard on all self-contained Capsule Pak™ refrigeration systems. On remote Split-Pak™ systems, it is standard on freezer systems 6 H.P. and above and optional on other systems.

The Master Controller completely removes frost build-up in coils and works much faster than electric defrost heaters. Its patented design also saves up to 27% more energy than an all-mechanical system.

Food Safety

The Master Controller’s reverse cycle defrost function helps prevent food spoilage because it completely and rapidly removes ice build-up in evaporator coils. Reverse cycle works from the inside of the coil outward compared to less efficient methods that work from the outside in. The average time using defrost heaters is 20-30 minutes. Reverse cycle can perform a completely “clean” defrost in as little as 3 to 5 minutes in a freezer or 1-1/2 to 2 minutes in a cooler.

How much energy can you save with reverse cycle defrost? See a map showing estimated energy savings for the U.S. 

Should there be an issue with the refrigeration system, operators will know instantly through error codes and data provided through the online web portal.

Installation Savings

As an integrated component of Capsule Pak systems, no installation is required. On Split-Pak systems, no wiring is required between evaporator coils and condensing units (2 pairs of low voltage wires, typically thermostat cables, are required to operate the Reverse Cycle Defrost valve and the compressor relay at the condensing unit). In some cases, the savings on wiring installation alone covers the cost of the Master Controller.

Additionally, on Split-Pak systems, a Master Controller-equipped system uses less refrigerant with no winter charge necessary.

Energy Savings

The Master Controller is designed to save energy in many ways:

  • Patented design saves up to 27% more energy than an allmechanical
  • Demand Defrost technology initiates defrosts only as needed
    for further energy savings
  • Defrost time, when initiated, is also greatly shortened
  • Reverse cycle defrost option on remote Split-Pak systems
    provides additional savings
  • On Split-Pak systems, save 2-4% more energy with the fan
    cycle option which saves electricity by cycling the evaporator
    fans during the compressor’s off cycle


Because each Master Controller is accessible through any web browser, you have complete 24/7 control from anywhere on the globe. Software loaded on each controller allows you to remotely monitor and program all data and setpoints using any device with a wireless internet or cabled (cat 5) connection*. There’s no need for a service tech to climb onto a roof or enter the walk-in to monitor or adjust the refrigeration system. Plus, constant access to data allows users to improve refrigeration system performance and avoid service issues.

*Internet connection not required for controller operation.