How Differential Pressure Gauges Affect HVAC Checks

February 11, 2022

When ensuring optimum indoor air quality, HVAC technicians must account for a range of factors such as airflow, relative humidity, and particulate build-up. Whether individually or collectively, these factors can have a significant impact on performance and comfort. There are several instruments used by HVAC professionals to monitor and check said factors, one of which is the differential pressure gauge.

Differential pressure gauges and HVAC checks

Speak with an expert about how our differential pressure gauges can improve HVAC checks

How do Differential Pressure Gauges Work?

Differential pressure gauges for HVAC work on the principle of high and low pressure causing varying levels of airflow. Regardless of application or location, the majority of HVAC systems have a pipe or duct airflow, wherein filters cleanse the air passing from outdoors to indoors. Once filtered, the pressure of the air on the downstream side of the filter drops, which in turn pulls more air from the outside into the pipe.

By measuring the pressure at points on either side (inside and outside) of a filter system, HVAC technicians can assess particulate build-up in the air and the condition of the air filter–two factors that contribute to the change in pressure. This assessment requires a predetermined threshold that will clearly illustrate when differential pressure has dropped too low. This threshold is set by calculating the volume flow rate and identifying the filter’s physical characteristics, such as thickness and age.

How does Pressure Switch Data Help Improve HVAC System Checks?

The most important use for a differential HVAC pressure gauge is to evaluate the performance of an HVAC system. For example, a blocked air filter is the number one cause of a significant change in pressure measurement. If left unaddressed in the short term, this blockage will reduce the effectiveness of the HVAC system. Long-term negligence will eventually cause the system to break down, leading to expensive replacement costs.

Differential pressure readings can also indicate a serious issue within a tube or pipe. For instance, if an air filter is not just blocked but there has also been considerable damage to a tube or pipe, the HVAC system’s effectiveness will decrease profoundly, leading to costly equipment repairs or replacement much sooner than normal. Also, data outside of a normal range could indicate an airflow problem before gasses even reach a filter. Regardless of the specific problem, differential pressure gauges give HVAC technicians the insights needed to make more informed decisions about system maintenance and repairs.

In addition to system maintenance, HVAC techs can use pressure gauge measurements for broader planning within the overall ventilation system. For example, a blocked air filter inside a ventilation system causes pollutants to leak through the blockage, contributing to increased particulate build-up in an indoor space. Concurrently, restricted ventilation airflow facilitates a drop in indoor air pressure, forcing the system to suck in more air from other areas to fill the vacuum. In a worst-case scenario, this unbalanced differential air pressure will contribute to the entire HVAC system breaking down and a comprehensive decrease in indoor air quality. But with timely pressure gauge measurements, all of this can be easily avoided.

Mid-west Instrument primarily serves the commercial HVAC industry. Our diaphragm type differential pressure instruments are designed to measure the pressure differential in transformer oil cooling systems. Particularly, our Model 140, Model 142 and Model 522 are the best pressure gauges for use in the commercial HVAC industry.

Contact our representatives today to learn how our Differential Pressure Gauges can be used for your HVAC application.