One example of an application for digital-based electronic controllers is on a supermarket rack system where six PressuRITE controllers were installed. Each controls low pressure, high pressure and oil pressure. (Photo courtesy of The Product Group.)

Digital-based electronics are being used in refrigerant pressure controllers that operate commercial compressor and condenser equipment.

“Our control removes the last, weakest link in all refrigeration and air-conditioning systems that until now has not been digitalized,” said James Italiano, manager of products and business development for The Product Group, which is marketing its pressure controller under the brand name PressuRITE™.

“That weak link would be the existing 70-year-old technology of mechanical bellows/cap-tubes and springs/levers pressure switches.”

According to Italiano, The Product Group’s controller brings “low pressure, high pressure, and oil pressure up to current 21st century technology.”

The new controller (it’s been in national distribution for over nine months) uses adjustable digital electronics, he said, to read the signals from its proprietary electronic pressure sensors that are attached to a refrigeration pumping compressor at its high, low, and oil pump discharge ports.

“Since it works on any refrigerant, any pressure, any range and any set point, the controller can then be used to operate any commercial refrigeration compressor/condenser equipment, large commercial air conditioning equipment, condenser head pressure (for fan cycling operation), and for water cooled condenser heat pump loop control to eliminate nuisance pressure trips and provide temporary system operation.” The technology also will deal with keeping compressor failures and reset problems to a minimum, he said.

“Because it is digital, it is very accurate in sensing and controlling the equipment it’s applied to. The service technician sets the control to the desired on-off set points via button selections with a setup tool provided with each controller.

“Then when the setup is complete (it takes two minutes), the technician hits a final keystroke and the sensors/transducers are automatically calibrated to atmospheric pressure for the altitude at which it is located. The sensors are then connected to the same location that any ¼-inch flare cap-tube device normally would attach to. One-psi accuracy is then delivered to the user.”


One example of an application is on a supermarket rack system where six PressuRITE controllers were installed. Each of the controls operates low-pressure control and high pressure limits (oil pressure will be added in the near future).

“Bennett’s Refrigeration Service Company out of Little Rock, Ark., used these controls with great success on this refrigeration rack as well as on individual condensing units,” according to Italiano.

He continued, “It solved a lot of mechanical control failures and improved system reliability which Bennett’s was responsible for. The installation took about the same time as bellows controls, but the set up for the controller operation takes only a few minutes rather than close to an hour with other methods.”

In this application, the systems were set up to be “auto-reset” for high-pressure. (Either Auto or Manual High Limit Re-Set is selectable.)

“Once it is installed, the technician needn’t ever reattach refrigerant service gauges to that system again just to perform routine maintenance. Instead, the technician connects his setup tool (the hand-held programmer) to the controller and in seconds all the set points and pressures in the system are displayed in real time for the technician to see … without any refrigerant gas release,” said Italiano.

He maintains that their product replaces more than 140 different models of commonly used bellows/cap-tube pressure device configurations, and does it while eliminating refrigerant loss due to broken cap tubes and seeping bellows, and the technology can be offered at a comparable price.

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Publication date:06/01/2009