Field Notes
Plain-language notes on components, circuits and how to read a schematic, written for people at the bench, not for a classroom.
Field Notes
Why Do Some Evap Coils Leak While Others Do Not? (Quick Tip)
Why do older coils seem to last a long time but ones that are only 10 or 15 years old leak? Energy transfer efficiency was not as much of a concern on older equipment ...
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40 Vacuum Tips for HVACR Technicians! Avoid Frustration!
I put this list together to make sure that HVACR technicians don’t have to undergo the same frustrations, loss of time, and expenses that I did when trying to figure o...
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Checking the Charge of Air Conditioners Without Measuring Pressure!
Can you check the charge on a system without checking pressure? Sure, remember that the only reason we check pressure is to convert it to saturated temperature. For si...
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Can I measure a Negative Subcooling When Checking the Charge? (Quick Tip)
The answer is no because the refrigerant rejects heat in the condenser so the pressure and temperature of the refrigerant should lower. The refrigerant starts off in t...
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R-22 and R-410A Operating Pressures, Charging, and Recovery Setup!
In this article, we will discuss an HVAC unit’s refrigerant pressure on both the high side and the low-pressure side while the system runs. It is important to know the...
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Charging a System in a Dry Climate? Consider a TXV and Accumulator!
In a dry climate, certain considerations must be taken prior to installing or servicing air conditioning systems. A TXV metering device and an accumulator are importan...
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