Your Resource for All Things Compressors
This page serves as your go-to hub for all things compressor-related from CMP Corporation — including educational videos, technical how-tos, maintenance tips, and product insights. Whether you’re a technician, distributor, or engineer, you’ll find the knowledge you need to keep compressors running strong.
Changing a Carrier Compressor Valve Plate
A:C and Refrigeration Principles and Diagnostics
Changing a Copeland Compressor 4R/6R Valve Plate
A1 FINAL TEST PROCESS
How To Install an 06E & D Carrier HGBP Unloader
How To Change a Copeland K Model Valve Plate
Changing a Carrier Compressor Valve Plate
06D&E HEAD GASKETS
How To Wire an 06E 9 Lead 460 Volt Carrier Compressor
How To Install an 06E & D Carrier HGBP Unloader
How To Part Wind Start Wire a 06E Carrier Compressor
Make Sure Your Compressor is Functioning Properly
Your compressor is now installed, run-tested, and charged. It seems to be running great, but you should double-check.
Follow these four basic steps:
Check to be sure gauge pressures are typical for the particular ambient and box temperature.
Check key components such as amp draw, oil level, and Super Heat. A good rule of thumb is 20 degrees at the compressor.
A good mechanical contractor will always return the next day to see that these critical indicators are holding. Remember- The goal is a satisfied customer.
Make sure that you always replace the contactors and driers, and perform a thorough inspection of the electrical system every time you replace a compressor.
Remember, you only want to change the compressor once. Therefore, finding the reason for the failure is essential.
Top 10 Reasons Why Your Compressor Failed
Lack of Preventive Maintenance
PM is hard to sell by itself in this economy, but you can always include PM in every Service Call. Your customer will appreciate your efforts.
Key Components Not Changed
Contactors and Relays can cause motor burn. Always check the compressor amp draw against the FLA of the compressor.
Dirty Condenser and Evaporators
This is a PM item. You cannot properly charge a system with a dirty condenser and/or evaporator.
Worn Pulleys and Belts
The number one overlooked A/C fault. Constantly adjust the pulley, then the belt, then set the blower amp draw close to the full load amp draw of the motor with doors closed.
Low Refrigerant Charge
This is the worst thing that can happen to an A/C system. System icing will always damage the compressor.
Misadjusted Expansion Valve
Poorly adjusted valves will cause liquid flood back, thinning the oil and damaging the compressor.
Liquid and Oil Slug Upon Start Up
Here, a pump-down system or adding a suction line accumulator is the best defense against these conditions.
Liquid Floodback
Preventing LF is as simple as cleaning the evaporator and filter and checking the Super Heat. Super Heat should be no less than 20 degrees at the compressor. Compressors are meant to pump vapor. Any liquid that reaches the cylinders of the compressor is a potential cause for damage.
Safety Controls
Ensure your low-pressure switch prevents your system from running into a vacuum.
Mismatched Oils and Refrigerants
Identify the oil used in the compressor and the corresponding refrigerant. With over 100 refrigerants and three different oils, it's easy to mismatch the oil and refrigerant inadvertently.
Probably the most important thing to remember is that a well-maintained electrical system and correct Super Heat at the compressor, as a rule, will almost always prevent costly compressor failures.
8 STEPS TO A HEALTHY COOLING SYSTEM
A good PM program should include a complete review of the components in the refrigeration and/or HVAC system. The components should be cleaned, tested, and function to ensure that the system will operate as intended. This system review should be performed at least annually. The benefits will include a smooth-running system and a lifelong customer.
Contactors/Relays
Good clean power allows for a smoother start and better RLA. Always check the AMPs of the compressor, keeping in mind that the RLA is figured when the room or box is at its hottest.
Evaporator Blower Motors and Belts
Adjusting the pulley close to the tag FLA will maximize the Air Flow across the coil. Raise the suction pressure, and the system will work like new.
Condenser/Evaporator Maintenance
They must be serviced and cleaned; otherwise, the systems will experience a downward trend, ultimately leading to a failed compressor. In refrigeration systems, a key component that needs to be checked during all PM visits is the Fan / Defrost Termination Switch. Be sure to check it for proper operation so that water freezes on the coil before the fans come on.
Adjust the Unloader
If unloading does not occur, then flood back can take place, which will lead to compressor damage.
Check Super Heat
20 degrees at the compressor and 10 degrees at the TEV bulb are usually ideal. Remember that the true superheat is when the room or box has reached its lowest or required temperature.
Safety Controls
Safety Controls typically will last the life of the system. They should, however, be checked for proper settings at least twice a year.
Oils—Check the Level
Oil levels should be between ½ and ¼ sight glass on most compressors, depending on the compressor make and model.
Crank Case Heaters (if equipped)
The crankcase heater usually is ON all the time, even when the unit is not running, though temperature sensors and set points may be used to turn it off when not needed.