What is the maximum acceptable pressure differential between HEU and EOT readings when installing an EOT?

What is the maximum acceptable pressure differential between HEU and EOT readings when installing an EOT?

• A. No more than 5 psi
• B. No more than 1 psi
• C. No more than 3 psi
• D. No more than 2 psi

Answer: (C)

The main idea here is to ensure the EOT is installed in a way that won’t be stressed or give you unreliable readings due to a large pressure difference across it. When you set up an EOT, the pressure at the upstream side (HEU) and the downstream side (EOT) should be very close. A small differential means the EOT is effectively sitting in a near-static condition, so the sensor/diaphragm isn’t fighting a big flow pressure, which helps keep the reading accurate and protects the device from extra load. No more than three psi is the chosen limit because it provides a balance between measurement accuracy and practical installation tolerances. If the differential were larger, you’d start to introduce nonlinearities, drift, or potential damage from the pressure load on internal components. Keeping it at or below three psi ensures the EOT can calibrate correctly and operate reliably within its intended range. If you see a greater differential, recheck the installation path, connections, and any nearby valves or restrictions. There may be a leak, a partially closed valve, or an obstruction causing an unavoidable pressure drop that needs correcting before finalizing installation.

The main idea here is to ensure the EOT is installed in a way that won’t be stressed or give you unreliable readings due to a large pressure difference across it. When you set up an EOT, the pressure at the upstream side (HEU) and the downstream side (EOT) should be very close. A small differential means the EOT is effectively sitting in a near-static condition, so the sensor/diaphragm isn’t fighting a big flow pressure, which helps keep the reading accurate and protects the device from extra load.

No more than three psi is the chosen limit because it provides a balance between measurement accuracy and practical installation tolerances. If the differential were larger, you’d start to introduce nonlinearities, drift, or potential damage from the pressure load on internal components. Keeping it at or below three psi ensures the EOT can calibrate correctly and operate reliably within its intended range.

If you see a greater differential, recheck the installation path, connections, and any nearby valves or restrictions. There may be a leak, a partially closed valve, or an obstruction causing an unavoidable pressure drop that needs correcting before finalizing installation.