Defrost in Commercial Refrigeration w/ Dick Wirz

February 1, 2018

Author of commercial refrigeration for air conditioning technicians, Dick Wirz talks to us about refrigerator and freezer defrost strategies.

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HVAC School – For Techs, By Techs

Real training for HVAC ( Heating, Ventilation, Air Conditioning and Refrigeration) Technicians. Including recorded tech training, interviews, diagnostics and general conversations about the trade.

In this episode of the HVAC School podcast, Bryan welcomes back Jim to discuss the groundbreaking SureSwitch contactor technology from Copeland. This isn’t just another incremental improvement – it’s a complete reimagining of how contactors should work in modern HVAC systems. Jim brings his expertise and even demonstrates the technology with a special cutaway camera setup, giving listeners and viewers an inside look at this innovative solution.

The conversation begins with the evolution of contactors in the HVAC industry, explaining how manufacturers moved backward from heavy-duty two-pole contactors to lighter, more cost-effective one-and-a-half pole designs. While this cost reduction made sense for manufacturers, it often left technicians dealing with more frequent failures and replacements. The SureSwitch represents a leap forward, combining the reliability of traditional heavy-duty contactors with modern electronic intelligence and enhanced protection features.

One of the most compelling aspects of the SureSwitch is its multi-voltage coil capability, supporting 24V, 110V, and 240V applications with a single unit. This flexibility dramatically reduces inventory requirements for contractors and service companies, allowing one contactor to handle residential HVAC, refrigeration cases, ice machines, and pool heaters. The universal application makes it particularly valuable for smaller businesses that need to stock fewer SKUs while maintaining the ability to handle diverse applications.

The technical innovation behind the SureSwitch’s longevity is fascinating. Using an optical sensor (described as a “little eye” in the sealed chamber), the contactor monitors for electrical arcing during contact opening and closing. The built-in microprocessor analyzes the 60Hz AC sine wave and times the contact operation to occur at the zero-crossing point, eliminating destructive arcing. This “no-arc zone” operation, combined with latching contacts that prevent chatter during brownout conditions, results in contacts that remain clean and functional even after a million cycles – five times longer than traditional contactors.

Key Topics Covered

· Contactor Evolution and Industry Innovation

o Historical perspective on contactor design changes from heavy-duty to cost-optimized

o Why the HVAC industry needed to innovate forward rather than continue cost-cutting

· Multi-Voltage Flexibility

o Single contactor handles 24V, 110V, and 240V coil applications

o Reduces inventory requirements and simplifies contractor operations

o Applications include residential HVAC, refrigeration, ice machines, and pool heaters

· Arc-Free Contact Technology

o Optical sensor monitoring system for detecting electrical arcing

o Microprocessor-controlled timing to operate at AC sine wave zero-crossing

o Five times longer contact life compared to traditional contactors

· Chatter Elimination and Latching Mechanism

o Internal power supply eliminates dependency on weak control voltage

o Magnetic latching system prevents contact bouncing during brownout conditions

o Protection against undersized control wiring and long wire runs

· Sealed Contact Chamber Design

o 100% sealed contact chamber prevents insect and debris contamination

o Eliminates common failure modes from ants, earwigs, and lizards

o Reduces need for pest control interventions

· Built-in Compressor Protection Features

o Brownout protection with automatic voltage monitoring (184V threshold)

o Random start delay (0-90 seconds) for multiple unit installations

o Short cycle timer protection working independently of thermostat timers

· Installation and Compatibility Considerations

o Compatible mounting holes with standard contactors

o Proper crankcase heater wiring configurations

o Training considerations for technicians adapting to new terminal layout

· Warranty and Business Applications

o 10-year warranty vs. standard 1-year contactor warranties

o Good-better-best selling scenarios for contractor businesses

o Applications in high-end residential and commercial installations

Learn more at the SureSwitch at http://www.hvacrschool.com/SureSwitch.

Have a question that you want us to answer on the podcast? Submit your questions at https://www.speakpipe.com/hvacschool.

Purchase your tickets or learn more about the 6th Annual HVACR Training Symposium at https://hvacrschool.com/symposium.

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Check out our handy calculators here or on the HVAC School Mobile App for Apple and Android

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