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
Top 10 Gas Furnace Package Unit Problems!
Common gas furnace package unit failures, starting with checking for power at the control board LED.
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Carbon Monoxide Alarm vs Low Level CO Monitor
Compares standard CO alarms with low level CO monitors, and the health effects of low level carbon monoxide exposure.
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Measuring Airflow in CFM Using the TrueFlow Grid
Airflow is often skipped due to a lack of easy methods and tool accuracy limits. A review of the options and how the TrueFlow Grid measures CFM.
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Measuring the Static Pressure Drop Across an Evaporator Coil to See if it is Clogged!
Static pressure readings reveal how restricted a hidden evaporator coil has become.
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5 Methods to Determine if The Indoor Air Conditioning Coil is Clogged with Dust!
Dust buildup from missing or poorly fitted filters reduces airflow and efficiency. Five ways to detect a clogged indoor coil.
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Seeing the TXV Metering Device Operate Using A Water Stream!
A classroom project that uses a water stream to show how a TXV or piston changes liquid flow, making metering device operation visible rather than abstract.
Read more →Electronics, in plain language.
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