Magnehelic Duct Pressure Sensor - Magnehelic Duct Static PressureMagnehelic Duct Pressure Sensor - The magnehelic measures duct pressure inside of ductwork. It is important, for many reasons, to know the pressure inside of ductwork. This magnehelic measures the supply side pressure of the blower inside the air handler.

Magnehelic Duct Pressure Sensor

The static pressure in this system is actually controlled by a static pressure transducer which is directly hooked up to a DDC controller that controls a variable frequency drive based on static pressure. The static pressure transducer is a solid state magnehelic and works in much the same way a magnehelic works except the transducer is digital and sends out a signal that registers the pressure it is reading. The magnehelic pictured is simply for visual display and reading the static pressure inside the air handler. It does not send out any signals.

A technician can walk up to the air handler in a quick glance tell if everything is okay with the blower and duct system based on pressure. Pressure sensors with switches in them are also used to determine an air filter status. A differential pressure switch can be installed in an air handler with pressure probes on either side of the filter. A differential pressure setpoint is adjusted to the switch so that when the filters load up the switch trips and send a signal to the DDC controller. This alerts the operator of the system that the filters are loaded up and need to be changed. This differential pressure switch is usually calibrated and set using a magnehelic pressure sensor.

Magnehelic Duct Pressure Sensor

This can also be used to find problems with the air handler and ductwork system. If the pressure is too high or too low then the maintenance staff knows there is a problem that needs to be resolved. Example, dirty air filters will cause increased pressure on one side of the filter bank and low pressure on the other side. Tools like these add to the cost of the equipment but make things so much easier for the maintenance staff. They also increase reliability.

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Magnehelic Duct Pressure Sensor – Magnehelic Duct Static Pressure

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