Manometer

Measuring gas pressure and static pressure in inches of water column.

Tool

Apprentice

#manometer#static pressure#gas pressure#airflow

Safety

Gas pressure testing involves live fuel connections. Leak test every connection after reassembly and follow the manufacturer instructions.

What it is

A manometer measures low pressures in inches of water column. In HVAC it is used for two very different jobs: verifying gas manifold and supply pressure on a fuel burning appliance, and measuring static pressure in a duct system.

Static pressure

Total external static pressure is measured across the air handling equipment, between the return and supply connections, and compared against the equipment data plate. It is the single fastest indication that a duct system is restricting the blower.

Return Grille

Filter

Blower

Coil / Heat Exchanger

Supply Duct

Registers

Air distribution path

Where static pressure readings are taken

Gas pressure

Working on a gas system

Gas pressure testing involves opening a gas carrying connection on an operating appliance. It requires training, leak detection after reassembly, and adherence to the manufacturer instructions and local requirements.

Local Code Notice

Gas pressure testing, appliance adjustment and required qualifications vary by jurisdiction and adopted code edition. Verify local codes, permits and manufacturer instructions.

Symptoms

High static pressure
Related procedure

Practice & Mastery

Manometer Troubleshooting Scenarios2

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