The analog manometer, commonly referred to as a Magnehelic®, is a test instrument that has been around the HVAC industry for decades. Among many technicians in the field, it is still the test instrument of choice for measuring the static pressure of an HVAC system. This instrument can handle daily field use by a technician and is cost-effective. These qualities make it an attractive option to many who might be considering its digital counterpart. I’ll be looking at some of the basics of this test instrument and some unique benefits it offers in this article.
Analog manometers are available in a variety of scales for use in the HVAC industry. These instruments are also available in various pressure units varying from pascals and inches of water column (wc) to pounds per square inch. This is also one of the drawbacks of the analog manometer. Many technicians work over a wide variety of pressure ranges with the various types of systems they encounter. This will require a technician to purchase multiple manometers to cover the range of pressures they work in. Don’t purchase the largest scale manometer you may need and think it will be accurate enough for low-pressure measurements. It won’t. For measuring static pressure, the scale on an analog manometer needs to measure 0-1.0 inches of wc for best accuracy.