Household Appliances (White Goods) / Cooling Technologies / Metal Coaters / Motors, Fans & Blowers

Compressor Diagnostics

April 5, 2012

compressorMany of the appliances and equipment we encounter in our personal and professional lives contain some level of electronics and diagnostic technology that

gathers usage and operational data. From cell phones and UPS systems to forklifts and coffee makers, products across markets and industries are becoming smarter.

Within the last few years, we’ve seen an increase in the technology available that enables us to better manage and analyze that data, transforming it into actionable information. For example, through embedded electronics, sensors and diagnostic technology, we can find out exactly how our car is performing, pinpoint a faulty part and identify proven preventive maintenance steps that can be taken to prevent future issues.

The HVACR industry is no exception. For a number of years, electronics have been integrated into residential furnaces that perform diagnostics through an integrated circuit board, which continuously monitors the furnace’s operational performance. Electronic supervisory controllers in commercial refrigeration have managed systems to optimize performance while preserving food quality.

As technology and diagnostic capabilities continue to evolve, it is a natural migration that electronics are now being introduced in air conditioning and refrigeration systems. With electronics becoming more common in air conditioning and refrigeration systems, they are now being integrated into the heart of these systems: the compressor.

chart1
 
By 2013, outdoor units with compressor electronics are expected to represent nearly 40% of the market.

Much like the human heart, the compressor is the central organ that keeps the system running. Its primary function is to pump “life blood,” i.e. refrigerant, through the system to ensure optimal and efficient performance. In the human body, problems that occur with other organs will often manifest themselves through the heart, causing it to work harder and potentially stop functioning. This is also true for the compressor and its HVACR system.

It is for this reason that the compressor makes an ideal sensor for which to gauge the health of the entire system. Similar to an EKG monitoring the heart, we can monitor the signals or information provided by the compressor to detect symptoms that are causing less than optimal performance. We’re giving the heart a brain.

 

Why Compressor Electronics?

In recent years, OEMs have targeted reliability as the primary market factor for HVACR systems. This in turn has fed the market for equipment that can diagnose and protect itself from failure until a qualified contractor arrives for service. Electronics for HVACR systems have been around in control boards for many years, but a number of significant developments in compressor technology through the years have paved the way for smarter electronics to sense, monitor and interpret electrical and mechanical information within the compressor, and to provide system diagnostics, protection, verification and communication.

One of the most important industry issues driving the need for compressor electronics is the high rate of compressor warranty returns that are classified as ‘No Fault Found’ (NFF). It is estimated that approximately 30 percent of all air conditioning and refrigeration compressors returned under warranty are NFF.

This creates major inefficiencies and adds unnecessary cost throughout the supply chain. ‘No Fault Found’ warranty returns are not a new issue. They have existed for many years and have become an accepted part of the warranty and maintenance process. No level of contractor training and experience can completely eliminate misdiagnoses; and unfortunately, many misdiagnoses lead to costly replacement of a good compressor.

Sometimes it can be as simple as a contractor replacing the compressor because they detect a strange noise, which might be due to vibration. Other times, it might be that other controls in the system are preventing the compressor from starting. The ability to improve diagnostic accuracy would not aid contractors with faster, more accurate diagnoses, and help to reduce cost throughout the entire channel by reducing the number of compressors returned with NFF.

 

chart2Operational Pressures Facing End Users

Residential and commercial end users are both facing pressure to reduce costs, eliminate waste and increase efficiencies across their homes and facilities. As they look for areas to make improvements, they invariably focus their attention on the number one source of energy consumption: their air conditioning or refrigeration system.

A study conducted by Emerson Climate Technologies at a local joint vocational school found that HVAC students had a troubleshooting accuracy of 17 percent without the use of a diagnostics module. When these same students used a diagnostics module, their accuracy improved to 92 percent. That same study was also conducted with experienced technicians, whose accuracy with compressor electronics improved to 100 percent.

End users want to ensure that their systems continue to operate at the optimum performance level. If there is a problem with the system, they want it quickly and accurately repaired without any unnecessary costs or callbacks. For commercial end users, any unplanned downtime of the system could result in the loss of perishable food.

Supermarket, convenience store and other food retailer operators ultimately want to improve their bottom line. When it comes to refrigeration equipment, operators are faced with costly installations, perishable inventory, maintenance costs, and overall energy costs. By utilizing systems with compressor electronics, retail operators can be assured of quality installations, system uptime, reduced maintenance costs and tighter control of energy consumption.

 

Inside How Compressor Electronics Work

By sensing, monitoring and interpreting electrical and mechanical information from within the compressor, compressor electronics allow you to monitor the HVACR system as a whole on an ongoing basis. The detailed compressor and system information it delivers enables you to quickly and accurately identify performance issues.

Compressor electronics gathers three primary types of operating information:

1. Current signature of the compressor

2. Compressor protector behavior

3. Presence / absence of demand

 

This information is then interpreted by software algorithms to identify:

  • Conditions leading to out of the envelope compressor operations
  • System faults
  • Electrical issues
  • Escalating patterns leading to catastrophic faults

 

Directing Attentionto the Root Problem

The most common system and electrical faults that plague an air conditioning or refrigeration system, such as locked rotor, short cycling, high discharge temperature, or low oil pressure, can be detected through the use of compressor electronics.

Once the information has been gathered and problems have been identified, the compressor electronics module identifies the root cause of the problem, providing information to diagnose and optimize the system. In many cases, providing detailed information at the right time allows system-related problem areas or performance issues to be diagnosed even before they occur.

Without compressor electronics, service technicians would typically have to rely on years of technical experience, critical system measurements, good judgment and after-the-fact analysis when troubleshooting a unit. They may be able to run the system and duplicate the problem, but might never know with certainty what caused the issue. They might even replace the compressor or other components, when in fact the root cause of the problem is elsewhere in the system.

As technology and diagnostic capabilities continue to evolve, the compressor is truly becoming both the heart and central nervous system as an ideal sensor for which to gauge the health of the entire system and through which to gather key operating information.

 With the valuable in-depth system information provided by compressor electronics, technicians can make faster, more accurate decisions.  

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