Bob got a call from the dispatcher to go to an office building that has a 3-ton heat pump compressor that has been shutting off after startup. The fan would continue to run. The building maintenance man said that he had observed the shutting down of the compressor several times.

The actual frequency and tasks performed will vary from system to system. However, here are some generic maintenance tasks which can be applied to many refrigeration systems. These tasks can be divided into two groups: one for maintaining the cabinet and one for maintaining the refrigeration system.

This article explores how a restricted metering device will affect system performance and efficiency. The system is a commercial refrigeration system with a TXV as the metering device. The refrigerant being used is HFC-134a. Very similar results will occur if an automatic expansion valve (AXV) is used.

There’s a new tekkie product on the market almost every day - or so it seems. And the HVAC trade is certainly not immune to a deluge of new products, be they mobile for field applications or computer software/web portals for office workers. This article offers a glimpse of a potpourri of software and related products.

The good idea of sealing up a building to make it energy efficient had some unwanted side-effects. Lack of circulation or the inability of a building to breathe compounded the high humidity problem. Fortunately, the HVAC trade has remained a leader in providing information, answers, and products to combat the humidity problem.

Bob got a call to go to a convention center where the air conditioning system was not working. It was a 75-ton unit with one compressor. The system was many years old, but had been functioning fine, until now. After checking out the unit, an ohm check showed 0 resistance to ground.

The increased use of high pressure refrigerants has created new challenges for technicians, yet it is still possible to perform high speed recovery of high pressure refrigerants. The tips and practices in this article will help keep your refrigerant recovery speeding toward the finish.

Replacing a compressor is neither simple for a technician nor inexpensive for the customer. Before replacing a compressor, a technician needs to ensure that it is truly defective. Unfortunately, sometimes good compressors get replaced as a result of a misdiagnosed problem.

For this column I want to discuss a real life situation regarding poor cooling in a residence and reduced airflow coming from the registers in the house. The air conditioner is a three ton (36,000 btuh), HCFC-22, split type, air conditioner with the A-coil in the plenum of the furnace located in the basement.

Btu Buddy has met Bob for lunch to answer some questions that Bob had about yesterday’s service call. Bob asked, “Why did that motor have two contactors and so many wires going to it? It seemed very confusing. I am glad that I tagged those motor leads when I disconnected the motor. I never would have figured out how to reconnect the leads.”