A very common freezer repair trouble call is a frozen evaporator
coil. When you open the door to inspect the coil, look around for signs of
outside air migrating into the box.
Bob had changed a compressor and was just
about ready to charge the system when a problem arose. He pulled a vacuum down to 500 microns but noticed a rise in the vacuum gauge to 1,000 microns. There was a leak and Btu Buddy assisted him in finding it.
With this article, The NEWS is introducing a new online column called “Troubleshooting With Jim Johnson.” In this column, Jim Johnson, director of training for Technical Training Associates, will present a specific HVACR equipment problem and invite readers to submit their diagnosis.
Bob receives a call from the dispatcher to go to an office building that has a 100-ton system that is water-cooled. With the help of Btu Buddy, he finds that the water level in the cooling tower is low. They check the water fill circuit and discover a kink in the copper pipe.
When you energize a motor, you get two
outputs: a desirable one (work) and one that is not so desirable (heat).
Equipped with this knowledge, you can understand why one of the
criteria you must consider when selecting a motor for an application is the
effect of operating temperatures on that motor.
The temperature is 102° outside. The complaint is from a car dealership. The showroom temperature is 85° and the dealer is having a big sale the next day. Bob finds the a/c unit is already doing all it can. Btu Buddy shows Bob some tricks to get more out of the system.
The compressor’s discharge temperature can tell the service technician what is going on inside a refrigeration or air conditioning system. The compressor’s discharge temperature is a reflection of the hottest part of a refrigeration system, and there are limits as to how hot a discharge temperature should be. This article will explore discharge temperatures and their limits.
The chiller maintenance tool that contributes most to a chiller’s overall efficiency is the daily log. An accurate daily log will provide a daily snapshot of the chiller’s operating characteristics and make abnormal conditions easy to spot.
When we last visited with lead installer John and his helper Charlie, they had learned how to measure external static pressure on a new system. They were shocked to measure a high 0.98 inches of water column - and surprised when their trainer asserted the airflow through the unit was probably OK.
In this installment of the Btu Buddy series, Bob and Btu Buddy meet on another job that has a low charge. This unit has a thermostatic expansion valve (TXV). They determine the evaporator is starved for refrigerant and check to see why.