In this installment of the Btu Buddy series, Bob encounters a compressor with very low oil level. Btu Buddy explains that the low oil level is a normal function of this system for this time of year.

In order to service and troubleshoot an air-source heat pump system, a service technician must understand the unit's sequence of operation. Where the system varies from its normal sequence is a major clue to any problems.

The problem: A piston-type reciprocating compressor has valve damage, or the valves are not sealing for some reason. The result: an inefficient compressor. This is one of the most difficult service problems to diagnose because the system may still have some cooling capacity.

In this edition of the Btu Buddy series, Bob works on a system that is not cooling properly and finds that refrigerant is flooding back to the compressor. Btu Buddy aids in pinpointing and curing the problem.

In this installment of the Btu Buddy series, Bob works on a water-cooled chiller with a high-pressure control that has the unit off. Btu Buddy assists him in inspecting the cooling tower and finding the problem.

Contractors are facing increasing pressures to be more productive. Armed with the proper tools and knowledgeable staff, savvy contractors can overcome today's challenges.

The electronic expansion valve (EEV) operates with a much more sophisticated design than a conventional TXV. Here are some electronic expansion valve basics.

In this edition of the Btu Buddy series, Bob is called to a motel that is having a chiller problem. Btu Buddy guides him through his first job on a water-cooled unit.

Measuring airflow can be difficult and time consuming, but it can be useful to troubleshooters. An easy method of measuring the airflow through a system that uses electric heaters is provided here.