Mercer Valve Pressure Relief Valve 81-11151T18G11

The following general procedure is recommended for the inspection of an 8100 Series PRV.

New parts should be inspected.

1. Inspect the seat for cuts and abrasions. The seat is the non-metallic element in the nozzle subassembly.

a) If there are only minor scratches or abrasions, the seat may be polished and restored.

b) Polish the seat area lightly with a fine grade abrasive pad. Be careful not to damage the soft seat.

c) If the seat is damaged with deep abrasions and cuts, it should be replaced.

2. Referring to Figure 29, measure the diameter Ds of the nozzle. This diameter must be in the range of values listed in Table

ORIFICE SIZE - ½", NOZZLE DIAMETER Ds, in (mm), 0.620 (15.75) - MINIMUM, 0.622 (15.80) - MAXIMUM

ORIFICE SIZE -¾", NOZZLE DIAMETER Ds, in (mm) 0.914 (23.22) - MINIMUM, 0.916 (23.27) - MAXIMUM

Warning: Ensure the valve is not pressurized before starting the inspection

Cap and Seal Wire in good condition

Seal wire has the correct impression

Flanges Connections in good condition

Threaded Connection in good condition

Outlet free from corrosion or debris

External Surface free from damage

Valve Tag information corresponds to the service conditions

If any of the checks fail, do not proceed with the set pressure inspection and the leak inspection

Warning: This inspection requires trained personnel with PPE!

Enter the set pressure of the valve

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

Did the valve pass the set pressure examination?

Choose the method used for testing leakage

Did the valve pass the leakage test?

If the valve did not pass the leakage test, it should be removed for further testing.

Warning: This procedure requires trained personnel with PPE!

If system is not operational, report the issues to the maintenance team and stop the procedure

Is the outlet pipe still attached?

Are the internal parts observable for visual inspection?

Are block valves present for set pressure testing?

Enter the volume under the valve

For dependable performance, PRVs must be maintained regularly.

Mercer Valve Co., Inc. recommends its PRVs are inspected and tested annually.; After the valve has been in installed and a service history has been established, the testing and inspection frequency may be adjusted.

Some guidelines for testing frequencies are found in NB-23, API 576, and API 598.; Additionally, government jurisdiction should be reviewed.; When maintenance is done, qualified repair personnel should perform it.; Qualified repair personnel conducting the annual inspection and testing may alter the maintenance schedule based on the service conditions.

During the inspection, a visual inspection, a set pressure verification, and a leak check should be completed.; These tests can be performed while the PRV is installed on its system or when it’s on a testing bench.; The PRV can only be tested while on its application if there is a method and procedure to apply a controlled pressure to the PRV’s inlet without exceeding any limits of the system.

A visual inspection is used to identify if the PRV is installed properly, is correct for the application, and doesn’t have apparent problems.

Check the nameplate information to verify that the valve is installed on the proper service. A missing nameplate requires immediate addressing.

If the valve is installed on gas/vapor service, the nameplate’s capacity will indicate an air capacity at standard conditions.

If the valve is on liquid service, the nameplate will indicate a water capacity.

Check the seal wire. A broken seal wire indicates that an unqualified person has adjusted the set pressure this also removes any warranty the valve had.