Setting up a refrigeration condensing unit for a walk-in cooler can present a challenge in foodservice applications.

Technicians can spend 25 minutes or more to properly adjust a mechanical low pressure control on a refrigeration condensing unit. These coarse adjustments tend to drift over time, requiring return service calls.

Mechanical low pressure controls (Figure 1) require:

• Hooking up a gauge set;

• Reading system pressure;

• Adjusting the mechanical pressure control with a wrench or screwdriver;

• Allowing system pressure to settle;

• Reading the system pressure again;

• Making any needed final adjustment(s) to the mechanical pressure control; and

• Removing the gauge set.

Contractors asked for a control they could set up more quickly that would not drift.


The Electronic Unit Controller (Figure 2) from Emerson Climate Technologies is now standard on many refrigeration condensing units. The controller reduces setup time and is designed to remain accurate over the life of the product. In addition, contractors can utilize the built-in diagnostics to more quickly troubleshoot any field issues.

“The Electronic Unit Controller from Emerson was easy to install and set. Our technician was very impressed by the accuracy of the pressure readings compared to his service gauges,” said Dan Whitten, Rosetown Central Refrigeration & Air Conditioning Ltd., Brampton, Ontario.

Emerson noted that overall benefits of the controller are:

• Setup time reduced from 25 minutes to one minute.

• Setpoint accuracy of 1.5 percent over the life of the product.

• Multi-refrigerant approval in one condensing unit.

• Built-in troubleshooting diagnostics.

• Added system safeguards.

• No cap tubes to break.

For more information on the Electronic Unit Controller, visit

Publication date: 10/10/2011