instructional guides

8 Steps to a Healthy A/C and Refrigeration System

April 15, 2014

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 functioned to ensure that the system will operate as intended. This system review should be performed at least annually. The benefits will be a smooth running system and a customer who will be yours for life.

8 STEPS TO A HEALTHY COOLING SYSTEM

1. 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.
2. 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.
3. Condenser/Evaporator Maintenance
   They must be serviced and cleaned or the systems on a downhill trend 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.
4. Adjust the Unloader
   If unloading does not occur then flood back can take place which will lead to compressor damage.
5. Check Super Heat
   20 degrees at the compressor and 10 degrees at the TEV bulb are usually ideal.  Remember that the true super heat is when the room or box has reached its lowest or required temperature.
6. Safety Controls
   Safety Controls normally will last the life of the system. They should, however, be checked for proper settings at least twice a year.
7. Oils—Check the Level
   Oil levels should be, on most compressors, between ½ to ¼ sight glass depending upon compressor make and model.
8. Crank Case Heaters (if equipped)
   The crankcase heater is normally 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.

For more information on developing a good PM program, call 1-800-743-6009.

Here Are the A-1 Compressor Top Ten Reasons Why Compressors Fail:

April 15, 2014

1. Lack of Preventive Maintenance
   PM is hard to sell by itself in this economy but you can always do your PM on every Service Call. Your customer will appreciate your efforts.
2. Key Components Not Changed
   Contactors and Relays which can cause motor burn.  Always check the compressor amp draw against the FLA of the compressor.
3. Dirty Condenser and Evaporators
   This is a PM item.  You cannot properly charge a system with a dirty condenser and/or evaporator
4. Worn Pulleys and Belts
   The number one overlooked A/C fault.  Always adjust the pulley then the belt then set blower amp draw close to full load amp draw of the motor with doors closed.
5. Low Refrigerant Charge
   This is the worst thing that can happen to an A/C system.  System icing always will damage the compressor.
6. Misadjusted Expansion Valve
   Poorly adjusted valves will cause liquid flood back thinning the oil and damaging the compressor.
7. Liquid and Oil Slug Upon Start Up
   Here a pump down system or adding a suction line accumulator is the best defense to preventing these conditions.
8. 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 deg at the compressor.  Compressors are meant to pump vapor.  Any liquid that reaches the cylinders of the compressor is a potential cause for damage.
9. Safety Controls
   Making sure that your low pressure switch doesn’t let your system run into a vacuum.
10. Mismatched Oils and Refrigerants
    Know  what oil is in the compressor and what refrigerant goes with that oil.   With over 100 refrigerants and basically 3 different oils, it is very likely that you can inadvertently mismatch the oil and refrigerant.

Probably the most important thing to remember is a well maintained electrical system and correct Super Heat at the compressor as a rule will almost always prevent costly compressor failures

For more information on developing a good PM program, call 1-800-743-6009

Make Sure Your Compressor is Functioning Properly

April 15, 2014

Your compressor is now installed, run tested and charged. It seems to be running great but you need to be sure.

Follow these 4 basic steps: 

1. Check to be sure gauge pressures are normal for the particular ambient and box temperature.
2. Check key components such as amp draw, oil level and Super Heat.  A good rule of thumb is 20 degs at the compressor.
3. A good mechanical contractor will always return the next day to see that these critical indicators are holding true.  Remember- The goal is a satisfied customer.
4. Make sure that you always replace the contactors, driers and perform a thorough inspection of the electrical system each and every time you replace a compressor.

Remember, you only want to change the compressor once.  So finding the reason for the failure is a must.

For more information on developing a good PM program, call 1-800-743-6009