Dwyer Differential Pressure Gage Magnehelic 2025

Disconnect pressure lines to vent both sides of gage to atmosphere

Are optional vent valves (bulletin S-101) used in permanent installations?

Magnehelic® Installation — Zeroing the Gage

Set the indicating pointer exactly on the zero mark using the external zero adjust screw on the cover at the bottom.

Are both high and low pressure taps open to atmosphere for zero check or adjustment?

Magnehelic® Installation — Operation

Maintenance — Calibration Check

Select a second gage or manometer

Connect the high pressure side of the Magnehelic gage and the test gage to two legs of a tee using short lengths of rubber or vinyl tubing

Very slowly apply pressure through the third leg

Allow a few seconds for pressure to equalize and fluid to drain

Return gage to factory for recalibration if accuracy is unacceptable

Ensure no field repair is attempted to avoid voiding warranty

Verify gage is returned to the factory for recalibration or repair if necessary

Check if bezel binds during installation and lubricate threads if necessary

Loosen bezel by turning counterclockwise using a canvas strap wrench or similar tool

Lift out plastic cover and 'O' ring

Remove scale screws and scale assembly carefully to avoid damaging the pointer

Adjust calibration by moving the clamp and tighten clamp screw

Ensure no lubrication is required

Ensure no periodic servicing is required