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AutoPurge System (APS) Field Tuning Instructions

Updated

This article provides general field tuning instructions for the AutoPurge System (APS) used with supported South-Tek N2-BLAST fire protection systems.

Proper APS tuning helps provide controlled purging at each riser while avoiding unnecessary nitrogen generator and air compressor runtime.

This article is intended for general setup guidance after the APS has been properly installed. Installation details may vary by system configuration.

Before you begin

Before tuning the APS, confirm the following:

  • The fire protection system is at supervisory pressure
  • The APS has been installed correctly at the riser
  • The APS ball valve is in the open position for normal operation
  • The correct APS model and corresponding setting information are being used

Basic APS tuning procedure

  1. Bring the fire protection system to supervisory pressure.
  2. Verify that the APS ball valve is in the open position.
  3. Turn the APS flow dial fully to the closed position by rotating it clockwise.
  4. Slowly rotate the APS flow dial counterclockwise until the center of the float bead reaches the alphabetical setting shown on the APS settings label.
  5. Allow the float bead to stabilize and verify the setting.

Using the APS settings label

The APS settings label is used to determine the proper alphabetical flow setting for the installed riser or zone. Use the label on the APS to identify the correct setpoint for the application.

Always confirm that the selected setting matches the installed APS model and the intended system configuration.

For a general reference of APS2 and APS4 flow settings by zone size, see APS Flow Settings Reference (APS2 and APS4).

Tuning APS when Quick-Check or PowerSaver is installed

If a Quick-Check purity manifold or PowerSaver manifold is connected to the APS, the tuning procedure is slightly different.

  1. Remove the 1/4" OD tubing from the APS adapter before adjusting the flow.
  2. Adjust the APS to the applicable setting for the installed configuration.
  3. Once the float bead has stabilized, reconnect the 1/4" tubing.
  4. After reconnecting the tubing, a slight drop in the float bead may occur due to manifold operation. This is normal.

Refer to the applicable APS setup information for the correct target setting when Quick-Check or PowerSaver accessories are installed.

Verifying the final setting

After tuning is complete, verify that:

  • The APS ball valve remains in the normal operating position
  • The float bead is stable at the intended setting
  • Any Quick-Check tubing connections have been reconnected securely
  • The system is operating normally with no unintended continuous purge condition

Important notes

  • The APS should be tuned only after the fire protection system is at supervisory pressure
  • The APS flow dial should always be started from the closed position before adjustment
  • Incorrect tuning may result in insufficient purging or excessive equipment runtime
  • If the system includes additional monitoring accessories, confirm all tubing and connections are restored after setup

If the APS does not appear to tune correctly

If the float bead does not stabilize at the expected setting, or if system behavior appears abnormal after tuning, verify the following:

  • The APS is installed in the correct orientation
  • The ball valve is open for normal operation
  • The fire protection system is at proper supervisory pressure
  • The correct APS model and settings are being referenced
  • Any connected Quick-Check tubing was removed and reinstalled as required during setup

If additional assistance is needed, contact South-Tek Systems support.

Need additional support?

  • Phone: (910) 415-1880
  • Email: support@southteksystems911.zendesk.com

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