This article is a guide for identifying the most common problems encountered in fans and air-handling systems. This is often an "art" and not a "science" because many problems are subtle and hard to diagnose.

In this installment of the Btu Buddy series, the customer's building is warmer than normal. Btu Buddy notes that this system has capacity control. Bob finds that one of the solenoid valves is not working.

There are a variety of things that can cause air conditioning freezing. The first thing to do is see if the indoor (evaporator-air handler) fan and compressor are both running at the same time.

Current starting relays are used on single-phase, fractional horsepower motors requiring low starting torque. Their main function is to assist in starting the motor. Start and run capacitors can be used in conjunction with current relays to boost both starting and running torque.

In this edition of the Btu Buddy series, Bob is dispatched to a home with water on the basement floor around the air handler. He determines that there is a condensate drain problem and he recommends installation of a condensate pump.

Regardless of your experience, to troubleshoot the system it is essential that you have a solid understanding of the fundamentals of refrigeration - including the principles of superheat and subcooling. You also need to have the right tools and know-how to apply these principles to use the tool quickly and efficiently.

In this installment of the Btu Buddy series, Bob is on a no-cooling call where the a/c system had just been repaired due to a refrigerant leak. Unfortunately, he discovers air in the system because it had not been evacuated.

Are you a technician that needs to do some troubleshooting on a totally dead air conditioning unit? Grab your tools and crank up the can-do attitude. Here are some tips for troubleshooting that air conditioner.

In this edition of the Btu Buddy series, Bob goes on a service call and finds a failed transformer in an electric furnace. He discovers that the heat relay in the system has a shorted coil.

If you want to keep equipment operating in peak condition, make sure you select the proper replacement fan blade when replacing a worn or damaged one. Proper fan blade selection can sometimes get overlooked.