4. Building Automation Systems_2022_ONEAC-Bldg 154, Air Compressor Replacement.pdf

METASYS AIR COMPRESSOR MONITORING AND PROCESSES

Normal Operations:

Total campus compressed air supplied by a single air compressor with the other air compressor in “Standby” mode.

LEAD = Unit that is currently running

LAG = Unit that is in Standby mode and able to assume load if needed.

Switching from LEAD to LAG Air Compressor for Maintenance or Servicing

Assuming Air Compressor #1 is running, and Air Compressor #2 is in Standby mode.

LEAD/LAG shall be commanded through Metasys by selecting AC1 or AC2 under the item “LEAD-AC”. The description shall read “AC1 is LEAD” or “AC2 is LEAD”.

To switch the compressed air system from one air compressor to the other, the operator shall command the “LEAD-AC” to AC1 or AC2.

This will begin the process to switch from Air Compressor #1 to Air Compressor #2 which shall be in standby mode.

If a fault is detected on Air Compressor #2 during the switching process, Metasys shall stop the process and post an alarm to the Metasys Event

Viewer. A software fault will also be generated.

Once the fault on Air Compressor #2 has been cleared, the process can be restarted by the operator by resetting the software fault on Metasys.

After the command is initiated to switch air compressors and no faults are detected, the 2-inch automated valve on the discharge side of the glycol cooling loop coming from Air Compressor #2 shall open. Air Compressor #2 shall start up once the glycol automated valve has proved open.

If the 2-inch automated glycol valve fails to prove open, an alarm will be sent to the event viewer on Metasys, and the switching process shall be stopped. A software fault will also be generated.

If no alarms are present and once Air Compressor #2 has reached the proper airflow rate and discharge pressure, the 3-inch automated compressed air discharge valve on Air Compressor #2 shall begin to open slowly.

At the same time that Air Compressor #2’s discharge valve is opening, Air Compressor #1 discharge valve shall begin closing slowly.

Air Compressor #1 shall also begin unloading and Air Compressor #2 shall start assuming the campus compressed air load.

Both air compressor discharge valves shall open/close slowly (time adjustable) to avoid damage to the discharge inline air filter.

Once Air Compressor #2 has fully accepted the total campus load, proven by system pressure(psi) and compressed air flow rate (CFM) operating at setpoints and the 3-inch compressed air discharge valve has proved open, the 3-inch automated compressed air discharge valve on Air Compressor #1 shall prove closed.

If the 3-inch automated compressed air valve on Air Compressor #1 fails to prove closed or the 3-inch automated compressed air discharge valve on Air Compressor #2 fails to prove open, an alarm shall be sent to the event viewer on Metasys.

If no alarms are present, Metasys shall show in the proper tab that the campus compressed air is being supplied by Air Compressor #2.

Air Compressor #1 is now in Standby mode.

Next, Metasys shall prove closed the 2-inch automated glycol valve on the discharge side of the glycol loop of Air Compressor #1.

If the 2-inch automated glycol valve fails to prove closed, an alarm will be sent to the event viewer on Metasys.

This process is the same to switch back to Air Compressor #1.

Loss of Air Pressure/Fault detected on Air Compressor:

Assuming Air Compressor #1 is running, and Air Compressor #2 is in Standby mode.

Upon loss of compressed air pressure below 90 psi (adj.) for more than 30 seconds (adj.) from Air Compressor #1, Air Compressor #1’s controller shall send a signal to Air Compressor #2’s controller to start up.

Next, Air Compressor #1’s controller shall send a fault message to the Metasys Event Viewer notifying the plant staff of an issue and Metasys shall show that there is a mismatch in what is actually running and what is programmed to run. A software fault will also be generated and will need to be reset before the air compressor can be put back in service.

If a fault is detected on Air Compressor #2 during this switchover process, Metasys shall stop the process and post an alarm to the Metasys Event Viewer. A software fault will also be generated.

If no faults are detected, the 2-inch automated valve on the discharge side of the glycol cooling loop coming from Air Compressor #2 shall open. After the glycol automated valve has proved open, Air Compressor #2 shall start up.

If the 2-inch automated glycol valve fails to prove open, an alarm will be sent to the event viewer on Metasys, and the switching process shall be stopped. A software fault will also be generated.

Once Air Compressor #2 has reached the proper airflow rate and discharge pressure, the 3-inch automated compressed air discharge valve on Air Compressor #2 shall begin to open slowly.

At the same time that Air Compressor #2’s discharge valve is opening, Air Compressor #1’s discharge valve shall begin closing slowly.

Both discharge valves shall open/close slowly (time adj.) to avoid damage to the discharge inline air filter and over-pressurizing the system.

Air Compressor #1 shall also begin unloading and Air Compressor #2 shall start assuming the campus compressed air load.

Once Air Compressor #2 has fully accepted the total campus load, proven by system pressure(psi) and compressed air flow rate (CFM) operating at setpoints, the 3-inch automated discharge valve on Air Compressor #1 shall prove closed.

If the 3-inch automated compressed air valve on Air Compressor #1 fails to prove closed or the 3-inch automated compressed air discharge valve on

Air Compressor #2 fails to prove open, an alarm shall be sent to the event viewer on Metasys.

Next, Metasys shall prove closed the 2-inch automated valve on the discharge side of the glycol loop of Air Compressor #1.

If the 2-inch automated glycol valve fails to prove closed, an alarm will be sent to the event viewer on Metasys, and the switching process shall be stopped. A software fault will also be generated.

The alarm details shown on Metasys shall match the fault information from Air Compressor #1’s controller and show that Air Compressor #2 has started and has assumed the campus load and is running within design specifications.

Once the fault has been cleared, Air Compressor #2 will stay as the LEAD until it is commanded otherwise by the operator. The faulted air compressor shall not start up on its own after a fault until the operator clears the alarms.

If Air Compressor #2 needs to remain as the LEAD air compressor, the operator shall edit the “LEAD-AC” value to AC2. This operation shall clear the mismatch alarm described above.

If Air Compressor #1 can be restarted and placed back in service, the operator shall reset the software fault and the air compressor shall start up and run as designed.

Any previous alarm conditions shall now clear from Metasys event viewer and return to normal.

Recovery from Power Outage (Utility Failure):

If a campus utility failure occurs, all of the automated valves on both air compressors shall fail closed.

An alarm shall be sent to Metasys that a power failure has occurred and both air compressors are stopped.

If a utility failure occurs on one of the air compressors, the faulted air compressor’s controller shall send an alarm to Metasys.

Once utility power has been restored and if no alarms or faults are present on either air compressors, the LEAD air compressor shall begin the startup process as detailed above.

AIR DRYERS

Process for switching between Air Dryers; Weekly rotation

LEAD = Online and in service

LAG = Offline and ready for service; standby

Rotating the Air Dryers

Assuming Air Dryer #1 is running, and Air Dryer #2 is in Standby

The following process can be performed either manually by a command from the operator to Metasys or on an automatic rotation schedule (adj.) set up in Metasys, however, before the LAG set of air dryers can be placed online and in service, Metasys shall monitor the LAG set of air dryers to ensure they have properly regenerated BEFORE the following process is performed. This shall be accomplished through a combination of monitoring the controller on the air dryer and the dew point sensor on the air dryer.

LEAD/LAG shall be commanded through Metasys by selecting AD1 or AD2 under the item “LEAD-AD”. The description shall read “AD1 is LEAD” or “AD2 is LEAD”.

If it is determined that the LAG set is not properly regenerated, the dewpoint is incorrect or a fault is detected, Metasys shall send an alarm to the event viewer and prevent the switch of air dryers from occurring by stopping the switchover sequence.

If no faults exist and the LAG set is ready for service, Metasys shall open the 2-inch discharge valve on the LAG air dryers.

Once the LAG discharge valve has proved open, Metasys shall close the 2-inch automated valve on the discharge side of the LEAD air dryer tower set and prove close on Metasys.

Fault detected on the Air Dryer

If the LEAD air dryer develops a fault on the controller, a message will be sent to Metasys indicating a fault is present. Faults that shall be communicated to Metasys: Inlet filter element change, Outlet filter element change, Failure to shift to Right tower, Failure to shift to Left tower.

Metasys will only attempt to switch over if the LAG dryer is ready for operation and the desiccant has been regenerated properly.

Switchover process shall be the same as described above under “Rotating the Air Dryers”.

Power Failure

If a power failure occurs on either air dryer, the controller on the de-energized air dryer shall send an alarm to Metasys indicating that a power failure has occurred.

After power is restored to the LEAD unit, any alarms/faults that are on the unit shall be communicated to Metasys.

If no faults are present, the air dryer that is designated as the LEAD on Metasys shall open its discharge valve and operate as designed.

General Monitoring; Air Compressors/Air Dryers

New automated valves shall fail in the closed position New automated valves shall be displayed as either open or closed using microswitches in the valve controllers.

New air compressors shall be connected to Metasys through a BACnet/IP protocol.

New air compressors shall be set up to communicate with each other per manufacturer recommendations.

Through Metasys, the operator shall have the ability to switch LEAD/LAG of the air compressors and the air dryers.

Metasys shall be able to automatically switch between LEAD/LAG when a fault is detected on the air compressor or a drop in pressure below 90psi for

30 seconds. Pressure setpoint and time shall be adjustable on Metasys.

Metasys shall display which air compressor/air dryer is in the LEAD.

Metasys shall display common alarm if air dryer has a fault.

Air Compressor #1 shall be labeled “AC1” on Metasys, and Air Compressor #2 shall be labeled “AC2” on Metasys.

Air Dryer #1 shall be labeled “AD1” on Metasys, and Air Dryer #2 shall be labeled “AD2” on Metasys.