How to Use a Magnehelic Pressure Gauge

By Bob White
A Magnehelic Pressure Gauge tells yout the pressure difference between two rooms.

A Magnehelic differential pressure gauge shows the relative pressure difference between two points. If both points have equal air pressure, the gauge reads zero. Such gauges are used in manufacturing, HVAC systems, painting booths, and venting, as both safety devices and a visual confirmation that the device is operating properly. Using a differential pressure gauge requires installing it properly and running air hoses from both points of the reading.

Choose a location to mount the gauge that is free from vibration and sunlight and does not exceed 140 degrees Fahrenheit. A location that is central to the two points and easily visible is also important.

Fasten the gauge in a vertical position to the wall by screwing it from the rear with four No. 6-32 machine screws.

Adjust the external zero adjust screw on the cover, at the bottom of the gauge, until it reads zero.

Connect the supplied pipe to the high pressure port located on the back of the gauge. Run the hose to the location you wish to read the high pressure.

Connect the supplied pipe to the low pressure port located on the back of the gauge. Run the hose to the location you wish to read the low pressure.

Plug the unused ports with the plugs provided.

About the Author

Bob White began his writing career in 2006. Working in sales, he was a technical writer tasked with responding to requests for proposal. White has a Bachelor of Arts in computer science and a diploma in home inspection. He has also worked in construction, landscaping and the pool industry for more than 15 years.