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How to test a regulator

December 7, 2023 By    

When regulators are installed or replaced, they should be tested to ensure they provide the correct volume and gas pressure for the appliances to operate.

We conduct these tests to determine if the system and regulators are sized properly for the appliance load and to ensure the regulator properly stops the flow when there is no demand from the appliances.

The system tests needed to confirm proper operation of the regulator are often referred to as flow and lock-up tests.

Testing definitions

Flow tests are often performed through either a full system test or a regulator test:

⦁ A system flow test monitors the pressure typically at the farthest appliance downstream of the regulator. It determines if the regulator is flowing the proper amount of gas to the appliance, assuming the system is properly sized for the demand.

⦁ A regulator flow test monitors the pressure at the outlet of the regulator and only shows the pressure coming out of the regulator.

⦁ The regulator lock-up test examines when the regulator has enough pressure under the diaphragm to allow the lever to seal the inlet of the regulator, stopping the flow of gas. The pressure will be greater than the flow and will not be the same every time, due to varying factors that affect lock-up. Since most appliances have a maximum allowable pressure of 0.5 psi (14-in. WC), the regulator lock-up should not exceed 14-in. WC.

Conducting the tests

All regulators should be verified and adjusted to provide the proper operation for the installed system.

The regulator should be adjusted for flow with the appliance operating. Insufficient gas flow can cause improper appliance operation and lead to unsafe conditions.

Overpressure situations can also potentially cause unsafe conditions, which is why we should ensure a proper lock-up test.

  • When conducting regulator testing, you should always be properly educated and use testing equipment your company approves.
  • First inspect the gas system, and turn off the supply of gas. Install testing equipment at the second-stage regulator and the farthest appliance downstream of the regulator.
  • Place the system into operation, and ensure all appliances are operating.
  • Check the gas pressure using a pressure measuring device attached to the farthest appliance with the entire load operating.
  • If the pressure measured is less than 11-in. WC, you should check the outlet pressure at the regulator.
  • If it is less than 11-in. WC, the regulator spring should be adjusted. The regulator adjustment is verified once the farthest appliance reads 11-in. WC.
  • Once this is accomplished, operation of all appliances should be shut off, including pilot lights, to ensure a no-flow condition.
  • Then ensure the regulator locks up at no more than 14-in. WC.

If a regulator has a lock-up pressure greater than 14-in. WC, the most common issue is debris between the orifice and the soft seat. This prevents the valve from fully closing, which will not allow the regulator to lock up.

On new installations, it is common to find piping shavings, dirt, mill scale and even excess thread sealant in the regulator. Most regulators will have a removable screen at the inlet of the regulator to catch debris and not allow it to pass into the regulator orifice and seat disc assembly.

You should verify the appliance manifold pressure for each appliance that is ready to operate. As with system regulators, appliance regulators need to be checked to ensure proper operation of the appliance.

Documentation, education

Documenting the testing results according to your company policy is the last important step. Ensuring you have results of the flow, lock-up and manifold pressures is important for the safe operation of the system.

The Propane Education & Research Council (PERC) has many resources available to assist propane marketers in obtaining training on regulator operation, including flow and lock-up testing.

Marketers can access these educational materials online, at no cost, through PERC’s Learning Center at training.propane.com.


Randy Warner is product safety manager for Cavagna North America. He can be reached at randywarner@us.cavagnagroup.com.

NOTE: The opinions and viewpoints expressed herein are solely the author’s and should in no way be interpreted as those of LP Gas magazine or any of its staff members.

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