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Home » Authors » John Tomczyk

Articles by John Tomczyk

The Professor: Controlling Evaporator, Defrost Efficiency

John Tomczyk
April 1, 2013

The evaporator is a major component in the refrigeration system, and an efficient evaporator plays a key role in saving energy. 


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The Professor: Partially Restricted Filter Driers

John Tomczyk
March 4, 2013

We are going to look at issues related to a partially restricted filter/drier. For this purpose I have included a service checklist as well as a number of illustrations.


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The Professor: Compressor Overheating

John Tomczyk
February 11, 2013

Compressor overheating is often referred to as the HVACR industry’s most serious field problem.


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The Professor: Compressor Superheated Discharge Temps

John Tomczyk
January 14, 2013
The compressor’s superheated 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.


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The Professor: Superheat Amounts and Total Superheat

John Tomczyk
December 3, 2012
There will always be a time when the evaporator sees a light load and the TXV may lose control of its evaporator superheat due to limitations of the valve and to system instability. What do you do then?


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The Professor: Superheat

John Tomczyk
November 12, 2012
Superheat is probably the most talked about yet misunderstood technical term used by service technicians in the field. Superheat is a measured value. What can be done with it?


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The Professor: Suction Line Accumulators

John Tomczyk
October 1, 2012
There are times when low evaporator heat loads, just ended defrost periods, failing or misadjusted mechanical valves, or simply lack of system maintenance can cause compressor floodback. If there is no way to prevent these periods of liquid floodback to the compressor, a suction line accumulator is needed on the system.


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The Professor: Frosted Compressor Head

John Tomczyk
September 3, 2012
Many service technicians believe that frost on a suction line or on the compressor’s head itself indicates there is liquid refrigerant coming back to the compressor. Is this really true? 


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The Professor: Systematic Troubleshooting an Oil-Logged Evaporator

John Tomczyk
August 6, 2012
Systematic troubleshooting using a system check sheet is still the best method for the conscientious service technician to pinpoint hard-to-find system problems. This article explores how evaporators can become oil logged, and includes symptoms with explanations of a system with an oil-logged evaporator.


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The Professor: Condensing Temperatures and Condensing Splits

John Tomczyk
July 2, 2012
The three functions of the condenser are desuperheating, condensation, and subcooling. Read to find out more about what the Professor has to say about these three topics. 


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