What a Differential pressure gauge is in HVAC and how to use it

An overview of why a differential pressure gauge is important for your air handling unit

Monitoring parameters for an air handling unit, such as temperature, pressure, or CO2 levels, is essential to controlling the environment in a given space.

The components responsible for gathering data about the environmental conditions both within and outside an AHU system are sensors, switches, and gauges.

In this article, we will concentrate on differential pressure gauges and respond to a few frequent questions about their importance to HVAC systems as well as how to use them.

What is a differential pressure gauge in HVAC?

A differential pressure gauge, in a few words, is a piece of equipment that serves as a crucial visual indicator of the difference in pressure between two pressure levels in an HVAC system.

The amount of air that flows through your system can be managed by differential pressures. In a generic HVAC solution, for example, the pressure measurement can regulate the damper setting.

Additionally, The levels of ventilation are adjusted following the demand and this will let you manage the volumes of fluids.

How is differential air pressure measured?

How do you express differential pressure? Simply put, differential pressure, often named Delta P, is the difference between two applied pressures: P = P1 - P2 in the given scenario.

How does a differential pressure gauge work?

Differential pressure gauges take the pressure at two different locations and show the difference in pressure between the two locations on a single dial.

DP gauges contrast the high-side pressure with a reference point known as the low-side pressure.

What is the difference between a pressure gauge and a differential pressure gauge?

As mentioned above, the Differential Pressure Gauge measures the pressure at two different places and compares these values, meanwhile, a normal pressure gauge checks the pressure in a single place only.

Differences between an Analog and a Digital Gauge

Analog gauges are mechanical tools and do not need any power source to work. It is a feature with a needle pointing to the level of pressure, this is how they display the measure to a user, and it is influenced by the changes in pressure.

Changes in temperature or flow are easily observed and kept track of as the needle moves.

Digital Gauges have a digital display/scale and provide a clear reading of pressure.

Pressure readings are shown on a digital indicator by digital pressure gauges using pressure transducers.

A power source, such as a battery, is required.

How do you use pressure gauges in an air handling unit? Where should a pressure gauge be placed?

Within an AHU, differential pressure gauges serve a unique purpose. They are often positioned near the filters with a monitoring scope.

Before and after the filter, the gauge records the pressure. When the gauge notices a significant difference in pressure, the filter is unclean and not allowing air to pass through as it should.

What is a Magnehelic differential pressure gauge? What is a Magnehelic pressure gauge used for?

Magnehelic gages are instruments for measuring very low-pressure differentials between two pressure sources.

The industry standard for measuring pressures in fluid amplifiers or fluidic systems, fan and blower pressures, filter resistance, air velocity, furnace draught, the pressure drop between orifice plates, and liquid levels with bubbler systems is the Magnehelic® gauge.

As well as monitoring blood and respiratory pressures in medical care equipment, it also inspects gas-air ratio controls and automatic valves.

A popular version of a Magnehelic Differential Pressure Gauge is the 2300-60PA - Dwyer Magnehelic Differential Pressure Gauge, a feature that measures air pressure, with an IP67 rating and a -30 to 30 Pascal pressure range.

What is a Magnehelic pressure gauge used for?

A gauge capable of either measuring pressure or differential pressure has different applications, such as:

• Filter monitoring in an air handling unit
• Air velocity
• Blower vacuum monitoring
• Fan pressure indication
• Duct, room, or building pressures
• Clean room positive pressure indication

Why you should use a Magnehelic differential pressure gauge in an AHU system

The benefits of using a gauge monitoring differential pressure are multiple:

• Patented design offers a quick response to pressure fluctuations, eliminating the need for delay in analyzing crucial situations. 
• Unique design offers a quick response to pressure fluctuations, eliminating the need for delay in analyzing crucial situations. 
• High accuracy option is twice as accurate as the basic Magnehelic gauge; 
• Rugged and durable housing; 
• High accuracy option is twice as accurate as the basic Magnehelic gauge;
• Rugged and durable housing; 

More examples of Magnehelic differential pressure gauge

A market leader with strong expertise in pressure gauges is Dwyer, and here the following ones are available in our store:

2300-60PA-HA has a Range 30-0-30 Pascal, High Accuracy included, and a Calibration Certificate.

2000-250PA has a range of 0-250 Pa, with minor divisions 5.0.

2000-60PA-HA is a Gauge measuring from 0 to 60 Pascal, including High Accuracy and Calibration Certificate.

2000-250PA-AHU2 has a range of measurement from 0 to 250 Pascal and includes a surface mounting plate & install kit.

Conclusion

We have given an overview of pressure gauges in this article, including what it is, how it functions, and where they can be used in HVAC systems and AHU units.

We would want to hear from you if you have anything to say that is pertinent to the issue or your personal experience.

Contact us at support@i-acs.co.uk if you require any further information or clarification.

support@i-acs.co.uk