2020 Tech Report May-June

Task # 2.b.: Performing Float Switch Testing on Liquid Make-Up Systems With- out a Drain Valve

ACTION

COMMENT

NOTE: Testing may take a significant amount of time to perform. Plan accordingly.

1.

This procedure will fill the Primary Vessel with liquid to the level of the tested float switch. Because of the amount of liquid required to fill the target vessel, verify that sufficient liquid ammonia is present in the Primary Vessel. There may not be enough pressure to move ammonia liquid into the target ves- sel and an ammonia transfer pump may need to be utilized. Shut down associated compressors us- ing a “Normal Shutdown.” Do not turn off the controls for the compressors.

This will require a special procedure. See your supervisor or facility contact.

2.

Refer to the corresponding SOP for each com- pressor. NOTE: This includes both compressors draw- ing vapor from or discharging vapor to this vessel. This may be a transfer solenoid, transfer pump, or transfer vessel. Consult your facility contact if you have any questions. Monitor the liquid level in the Primary Vessel during this operation. Verify that it does not fall below the minimum fill line. NOTE: During this operation, the pressure in the target vessel will rise significantly as there are no compressors drawing on this vessel.

3.

If installed, shut down and isolate the transfer system.

4.

Change the liquid make-up solenoid to the manual open position. If an electronic expansion valve is being utilized, manually open it.

5.

Ammonia liquid will fill the ammonia line piping and into the float switch column being tested.

RETA TECHNICAL REPORT PAGE 14