Active in the HVACR industry since the 1950s, Bill Johnson graduated in gas fuel technology and refrigeration from the Southern Technical Institute, a branch of Georgia Tech (now known as Southern Polytechnic Institute). He taught HVAC classes at Coosa Valley Vocational & Technical Institute for four years. He moved on to become service manager for Layne Trane, Charlotte, N.C. He taught for 15 years at Central Piedmont Community College, part of this time as program director. He had his own business for five years doing installation and service work. Now retired, he is the author of Practical Heating Technology and Practical Cooling Technology, and continues as a co-author of Refrigeration & Air Conditioning Technology, seventh edition, all published by Delmar Cengage Learning. For more information, he can be reached at 704-968-0000 or thebillj1@gmail.com.
Btu Buddy Notebook is a collection of more than 50 service call scenarios in book form covering both cooling season and heating season troubleshooting. For more information and to purchase the book, visit the HVACR Industry Store.
Their last service call is continued as Bob and Btu Buddy meet for lunch at the restaurant where the call occurred to discuss dew point. The duct through the dining room was dripping because the duct surface temperature was below the dew point temperature of the room and moisture formed on the duct surface.
Bob gets a call from the dispatcher that a new customer, a restaurant, has some ductwork in the dining room that has been sweating during the lunch hour for the last several days and dripping on the customers. It is about lunchtime so Bob goes to the restaurant to check it out. Btu Buddy helps in solving the problem.
This service call is for a routine checkup on an old 7½-ton unit using R-22. The call is going well until the owner mentions to Bob that the unit has actually never cooled well. Bob then proceeds to do a complete check of the system with Btu Buddy’s assistance.
Bob is a service technician who is well trained and nationally certified. However, he sometimes suffers from the same confusion that all technicians occasionally do - the facts that he gathers may or may not point to the obvious cause of the problem or the best solution. But Bob has something that no one else has.
Bob receives a call from the dispatcher telling him about a restaurant that is having difficulties. When he gets on the roof at the restaurant he notices that the unit's fan motor is turning, but seems to be very slow. As he approaches the condensing unit, the fan stops. With Btu Buddy's help, Bob diagnoses the problem.
Bob gets a call to go to an office building where its water-cooled chiller is not cooling the building. Bob finds that the suction pressure is a little low and the head pressure is about right but the unit is not cooling the water down to the 45°F design setting. Btu Buddy helps him in going step by step to solve the problem.
Warmer spring weather is here and Bob is beginning to get calls about units that are not cooling. He has just received a call from an old customer who said that her unit cools fine during the morning and daytime, but at night, it stops cooling. Bob investigates, and with Btu Buddy's help, finds the coil is dirty.
The customer had called another contractor and was not pleased with the results, so Bob’s company was called. The other technician said he could not get the compressor to start. With Btu Buddy’s help, Bob checks all the components that have to do with starting the compressor. He finds that the start relay needs to be replaced.
Bob and Btu Buddy sit down for a lunch discussion about humidifiers and Bob asks: “Aren’t all humidifiers about the same?” Btu Buddy responds, “They are all the same in that they add moisture to the air. Different homes have different types of heating systems.” He then discusses the ways water is evaporated in various humidifiers.
Bob receives a call from a customer who says her house is so dry that the wood is shrinking. Bob finds that the humidity level in the home is extremely low. Btu Buddy explains why this is happening in this older home and guides Bob in providing a solution.