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Articles by John Tomczyk

The Professor: The Needed Amount of Condenser Subcooling

The amount of condenser subcooling needed is system dependent. The more pressure drops — friction and static — associated with the lines and accessories that carry the liquid in the system, the more need there will be for liquid subcooling to prevent liquid line flash gas.


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The Professor: Why Is Condenser Subcooling Needed?

Condenser subcooling ensures that there is a liquid seal at the condenser’s bottom so the liquid line or receiver will not be fed with vapors. This condition prevents any noncondensables, like refrigerant vapor or air, from leaving the condenser’s bottom and entering the receiver or liquid line.


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The Professor: The Importance of Liquid Subcooling

This is the first of a three-part series covering the importance of liquid subcooling in a refrigeration or air conditioning system.


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The Professor: Helical Oil Separators

Oil separators are essential on low and ultra-low temperature refrigeration systems and on large air conditioning systems up to 150 tons. Most compressor manufacturers require oil separators on all two-stage compressors.


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The Professor: Megohmmeters for Preventive Maintenance

Megohmmeters (meggers) are electrical meters used to check the resistance and condition of the motor windings and the condition of the refrigeration and oil environment around the motor windings. A megger is nothing but a giant ohmmeter that creates a very large dc voltage (usually 500 volts dc) from its internal battery.


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Geothermal Comes in More than One Flavor

Since the tax credit program became available, all types of geothermal options have been on the minds of the building community. The earth loop, often referred to as the refrigerant loop, may be installed in three different configurations: diagonal, vertical, and horizontal.


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The Professor: Bad Compressor Valves

Many servicemen experience service calls where the compressor has both a low head pressure and a high suction pressure. There are three main reasons why a compressor will simultaneously have a low head pressure and a high suction pressure.


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The Professor: Systematic Troubleshooting of a Restricted Liquid Line

The problem in this scenario is a restricted liquid line after the receiver. Where do you go from here?


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The Professor: Chemical-Free Cooling Tower Treatment

When evaporation occurs in a cooling tower, only the water evaporates; it exits the cooling tower as water vapor, but leaves the minerals behind to concentrate in the cooling tower’s water system.
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The Professor: Loss of Air Conditioning Cooling

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.
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2014 SMACNA Annual Convention

Views from the 2014 SMACNA Annual Convention in San Antonio.

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NEWSMakers: Chris Mathis

Chris Mathis, president of Mathis Consulting Co. and vice chair of ASHRAE’s residential ad hoc committee, talks about ASHRAE’s exploration into the residential market. Posted on Oct. 17.

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2014 October 20

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EFFICIENCY STANDARDS

DOE has denied AHRI’s petition for reconsideration of walk-in standards. Is it getting harder to reach consensus on efficiency standards?
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