This article was originally published on April 3, 2023, and was updated on June 9, 2025.
In chemical and petrochemical systems, or any application that requires you to measure differential pressure (DP) with high static pressure and low differential pressure, reliability and corrosion resistance are crucial for safe instrumentation operation. If your pressure measuring instruments aren’t compatible with your process, you may face equipment damage and downtime.
Ashcroft has been a leader in pressure instrumentation since 1852. During that time, we have answered questions from customers about differential pressure and the measurement solutions we offer. In this article, you will get a quick overview of differential pressure and learn about two of the several differential gauges we offer, including the Ashcroft® 5503 DP Gauge and Ashcroft® F5504 DP Gauge. By comparing the similarities and differences, you can determine which may be a better solution for your specific application.
You will also see additional resources that you can explore to deepen your knowledge further about differential pressure and considerations for choosing pressure gauges.
What is differential pressure, and how is it measured?
Before we go into detail about differential pressure gauges, let's review the concept of differential pressure.
Differential pressure is the difference in pressure between two points in a system. This value provides critical insight into how fluids are moving, how components like filters or pumps are performing and whether systems are operating within safe and efficient parameters.
Differential pressure gauges are instruments specifically designed to measure this pressure difference. Unlike standard pressure gauges that measure against atmospheric pressure (also called gauge pressure), differential gauges provide the net difference between two points in the system. This is particularly useful for applications such as monitoring filters, pumps or liquid levels—scenarios where tracking pressure changes between two points is important to maintain a safe and efficient operation.
Common uses include:
- Filter monitoring: Identifying when a filter is clogged by measuring the pressure drop across it.
- Level measurement: Gauging liquid levels in pressurized tanks.
- Flow measurement: Indirectly calculating flow rate using pressure differential across a restriction.
These gauges are widely used in oil/gas, water/wastewater and biotechnology industries, as well as in HVAC systems to enhance performance, ensure safety and reduce unplanned maintenance.
Figure 1. Differential pressure illustration
High-performance differential pressure gauge for harsh environments
If your application requires high-performance differential pressure monitoring in demanding process conditions, a high-precision gauge like the Ashcroft® 5503 Differential Pressure Gauge checks all the boxes. This stainless-steel instrument is engineered with a dual diaphragm design for long-term durability. It can operate safely at extremely high static pressures to provide high visibility, reliability, corrosion resistance and safety. It has a pressure range from 10 in. H2O to 600 psi and is available with extensive customization options to meet specific application needs.
Compliance, ratings and protection features
- National Association of Corrosion Engineers (NACE) compliance for a Hastelloy® C276 diaphragm and housing
- ATmosphères EXplosibles (ATEX) approved (Optional) for use in explosive environments
- National Electrical Manufacturers Association (NEMA) 4X approval for an electrical enclosure that is designed to protect internal gauge components from harsh environmental conditions, including corrosion.
- Ingress Protection (IP) rating 65 and 66 for protection against dust and low-pressure water jets from any direction.
- Patented overload protection with internal mechanical stop design protects the sensing elements from damage due to pressure spikes.
Industrial and OEM differential pressure gauge
For high static pressure and low differential pressure applications with standard specifications, the Ashcroft® F5504 Differential Pressure Gauge is a cost-effective option offering fast lead times. This stainless-steel gauge also provides reliability and corrosion resistance while operating at extremely high static pressures. Its pressure range goes from 24 in. H2O to 600 psi, as well as offering three different accuracy options of 1%, 1.6% and 2.5%.
Compliance and protection features
- National Association of Corrosion Engineers (NACE) compliance for 316L stainless steel, Hastelloy® C276, and Monel housing
- Ingress Protection (IP) rating 67 for protection against solid particles, such as dust, and temporary immersion in water
Note: ATEX approval is not available for the F5504, making it better suited for non-hazardous or general industrial environments.
Differential pressure gauge comparison
The primary distinctions between these two differential pressure gauge models come down to customization, certification and fulfillment speed. Here’s how they compare:
Figure 1. Ashcroft Differential Pressure Gage Comparison Chart
With the use of capillaries, both of these gauges can be attached to our 200 and 300 series, with a Viton™ or Kalrez® diaphragm, the 700 Diaphragm Seal series, or a 3 in. or larger DF Flanged Flush Diaphragm Seal.
To ensure your seal is compatible with your process material and any pressure limit constraints, please see our Min/Max guide for reference.
Ready to learn more?
Now that you know the differences and similarities between Ashcroft’s 5503 and F5504 differential pressure gauges, you can determine which solution is best for your application. By considering the factors outlined in this article, you can prevent issues and ensure your process operates with dependable and precise pressure measurements.
For your reference, here are a few related blogs that may be of interest to you:
- What is a Differential Pressure Gauge?
- Why Use a Differential Pressure Gauge to Measure Flow?
- Choosing Measurement Instruments for the Chemical Industry
- How Accurate Are Your HVAC System’s Pressure Instruments?
Feel free to contact us today to talk to one of our industry experts and get your questions answered. In the meantime, please download our guide to see all the solutions available for harsh chemical and petrochemical applications. 