Mercer Valve Pressure Relief Valve 91-12L32TA7NA

Warning: This maintenance check requires qualified repair personnel!

Ensure to follow guidelines for testing frequencies as found in NB-23, API 576, and API 598.

Government jurisdiction should be reviewed.

Maintenance should be performed by qualified repair personnel.

During the inspection, a visual inspection, a set pressure verification, and a leak check should be completed.

Is the PRV correct for the application?

Does the PRV have any apparent problems?

Is the nameplate information correct?

Warning: This inspection requires trained personnel with PPE!

Set pressure of the valve verified?

Enter the set pressure of the valve

Contact Mercer Valve Co., Inc. for proper leak pressure and specification for the valve

Pressure held steady during the test?

Any leakage observed during the test?

There are several methods used in testing for leakage. Choose the appropriate one.

Choose the method used for testing

During the visual inspection, the pressure relief valve is checked for any potential issues that may restrict the operation of the valve

This inspection will be performed with the valve still assembled but the valve should not be pressurized for the safety of the person performing the inspection

Corrosion and damage to the valve are some of the common problems found in the visual inspection

Some of the items that should be checked in the visual inspection are as follows

Cap and Seal Wire - The valve cap and seal wire should be checked first on all inspections

These parts prevent adjustment tampering

On the seal wire, there is a pressed security seal that has an impression on it to indicate the certified company that last adjusted the set point the valve

When this seal wire is cut or removed, it indicates that someone may have adjusted the set point or altered the valve

This voids any warranty the valve had

Mobile testing units are similar to offsite testing

The valve is removed from the application

This enables a thorough inspection

Mobile testing units can save time because transporting the valve isn’t necessary

Mobile test units are often not set up to test all types and sizes

The testing equipment on a mobile test unit can vary

Some mobile test units have test stands similar to an offsite test stand, allowing for larger valves to be tested accurately

Other mobile test units are set up only for smaller valves

In each case, the limitations of the test stand should be documented and the test stand should only be used for the sizes and pressure that it is designed for;

Offsite testing allows for the most thorough and accurate testing and inspection

The valves are removed from the units and brought to a shop

In the shop, a valve can be completely tested and inspected

The shop environment gives the technician the most advantages because more tools are available, there is adequate space to work, and test benches enable accurate results

All of the same concerns in testing are still present in offsite testing as in situ testing

The volume of pressure, valve simmer, pressure losses to the gauges, and supply line pressure are all factors in getting an accurate result

Proper assembly of a test bench is crucial in limiting these effects

The main disadvantage in offsite testing is time

A valve must be removed from the unit and then transported to the shop