Magnehelic Gauges Review Wiki: Definition, Working Principle & Calibration of Differential Pressure Gauges

In industries like HVAC where monitoring the air pressure difference between two locations is of vital importance, the need for a reliable and accurate means to measure differential pressure is needed. There are several ways you can measure pressure but the simplest, and probably the best, way to measure this value is through the use of a magnehelic gauge.

Click here to see popular magnehelic gauges on Amazon!

What is a Magnehelic Gauge?

The simplest magnahelic gauge definition is that it’s an instrument used to measure pressure. It is mainly used in measuring positive or negative pressure (also known as vacuum); it also used to get the difference in pressures between two separate locations.

The magnahelic differential pressure gauge, or just magnahelic gauge for short, is the pressure gauge developed by Dwyer that can accurately measure pressure and pressure differences. In fact, the magnahelic gauge has set the industry standard in pressure gauges, and through the years Dwyer has been consistently raising the bar a little higher. Dwyer, ever since the company got started in 1931, has always been the industry front runner when it comes to controls and instrumentation technology.

Dwyer Magnehelic Gauge Specifications

Housing – The outer casing of the magnehelic differential pressure gauge is made of tough, die-cast aluminum, and powder-coated gray. It can withstand up to 168 hours straight exposure to salt water spray without any noticeable corrosion.

Accuracy – The magnehelic gauge can measure pressure difference at an outstanding accuracy of just plus or minus 2% at full scale.

Operating temperature – Magnehelic pressure gauges can operate efficiently between 20 degrees to 140 degrees Fahrenheit without losing accuracy, although this is just for the standard models. There are lower temperature models available upon request.

What Makes the Magnehelic Gauge Different from other Pressure Gauges

The thing that makes these gauges the best is that they incorporate the magnehelic principle developed by Dwyer. This principle gets rid of the problems that plague most of the other pressure gauges, problems like excessive wear, backlash, and toxicity. This results in a high-quality, durable, and accurate gauge.

Less Wear and Tear – The magnehelic principle is the patented method of transmitting the effects that air pressure has on a thin diaphragm to the indicator needle using only a magnetic linkage. This is the main difference that magnehelic differential pressure gauges have over the other gauges that use mechanical means to transmit the readings. This lack of physical contact between the parts mean that there is no wear inside the system that can affect the instrument’s accuracy in any way.

Fluid-less Design – There are numerous advantages to using Magnehelic gauge. Because there is no fluid present inside the instrument, the problems regarding accuracy loss due to evaporation or freezing is thereby eliminated. It also poses no risk of toxic contamination if the gauge gets damaged. The Magnehelic principle used in making these gauges also ensure a drift-free pointer movement that is not affected whatsoever by inertia.

High Durability – A magnehelic pressure gauge is extremely tough as well, considering the fact that it is a highly-sensitive measuring instrument. It can resist a respectable amount of shock and vibration, it is also relatively unharmed even when subjected to pressure surges of up to 15 psi, it is also unaffected by temperature fluctuations of up to 20 to 140 degrees Fahrenheit.

Easy Calibration and Installation – It is also a lot easier to calibrate a Dwyer Magnehelic gauge. The hoses just need to get disconnected and using the accessible adjusting screw on the cover, make the necessary adjustments until the needle points at zero. Installation is also a breeze, since the gauge is unaffected by gravity there is no need to install it at a level position.

Affordability – Despite being the best differential pressure gauge available in the market, the Dwyer Magnehelic gauge is very affordable. Though it employs cutting-edge technology to give users the most accurate pressure reading, it is still one of the most cost-effective instruments sold right now. Starting at just $55, these gauges certainly give a lot more value for money.

Applications of the Magnehelic Gauge

There are various applications where there are needs for an accurate pressure reading.

Magnehelic gauges are commonly used in HVAC applications; they are used to measure fan and blower pressures. They can also tell whether the air filters need replacement or not. These gauges also have medical applications, like monitoring air pressure in hospital respiratory apparatus and checking the air pressure in ‘clean rooms.’

Basically any application that needs an accurate pressure reading can benefit from the use of a magnehelic gauge.

Other Dwyer Products

Though Dwyer is known for the cutting-edge magnehelic gauge, they also offer other gauges and instrumentation equipment that have the same level of dependability. The most notable of these is the Dwyer photohelic gauge. This gauge operates on the same principle as the magnehelic gauge, and it also offers the same kind of accurate readings and durability you can expect from a Dwyer product. The main difference between photohelic and magnehelic gauges is that they can also function as switches; by using two relays inside the gauge, it is possible to set the low and high pressure limits to control blowers.

Where to Get the Dwyer Magnehelic Gauge

These gauges are available in all certified distributors; they can also be purchased online at the official Dwyer website or in online shopping portals like where one can avail of deals and discounts that can make the magnehelic gauge even more affordable than it already is. You can find these magnehelic and photohelic gauges from Dwyer through; you can also view the various customer reviews to see if these gauges are right for your air pressure measurement needs.

Magnehelic Differential Pressure Gauges

Before the magnehelic gauge came along, gauges were notorious for having a high degree of error in measuring the amount of pressure, and they are all very fragile instruments that need a very controlled environment to function properly. When the magnehelic gauge came along it changed the game entirely. It is highly durable that even after getting subjected to shock, vibrations and fluctuations in pressure and temperature it can still give pressure readings that are accurate within 2%. The Dwyer Magnehelic differential pressure gauge definitely sets the standard in accuracy and dependability in controls and instrumentation.

Click here to see popular magnehelic gauges on Amazon!

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