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Purge Guard

Redi Controls   Purge Guard Purpose of the Purge Guard There are certain control malfunctions which can occur with any thermal type purge regardless of make or model, such as welded relay contacts, locked-up microprocessor, or a unit accidentally left in manual mode, which can cause the pump-out compressor to latch-up in a non-stop running condition. Under these conditions the purge unit's built-in Excessive Purge Fault safety cannot stop the pump-out compressor and can result in catastrophic loss of refrigerant. The purpose of the Purge Guard  is to detect the above condition and terminate pump-out activity. Since the Purge Guard  functions independently from the purge unit’s microprocessor control it is able to terminate pump-out activity irrespective of the nature of the malfunction.  Product Information & INSTALLATION MANUAL          Wiring Instructions for Various Model Purgers

How the Purge Guard  works
A Purge Unit's non-condensable pump-out cycle time is normally about 2 or 3 minutes. A cycle time in excess of 2 or 3 minutes is generally an indication that a problem is developing. 
The Purge Guard  monitors pump-out compressor run time during each pump-out cycle.  If pump-out run time exceeds what is predetermined as a Normal Maximum Time, as pre-set on the Purge Guard  dip-switch, (e.g. 30 minutes), the Purge Guard  will automatically lockout purge pump out compressor operation. Purge activity will remain locked out until manually reset.
It is important to understand the difference between the purge unit’s normal Excessive Purge Fault and the Purge Guard  excessive pump-out compressor Run Time.  The Purge Unit's Excessive Purging Fault lock-out occurs whenever the cumulative pump-out time during any 24 hour period exceeds the maximum allowable time preset on the purge unit's Fault Time Dip Switch.  The Purge Guard  Excessive pump-out compressor Run Time lockout occurs whenever the pump-out compressor's ON  time exceeds the time value pre-set on the Purge Guard Dip Switch.

Application

The Purge Guard  is designed for application to any brand of Thermal Purger utilizing a pump-out compressor for extraction of non-Condensables. Although the instructions given here are for Redi Controls purge units, these same general instructions are applicable to other brands as well.
The primary installation requirement applicable to all thermal purge units is to re-wire the purge unit's control so that electrical power from the purge unit's controls which normally energizes the pump-out compressor motor and isolation solenoid valve is re-routed through the Purge Guard  relay.

The Purge Guard  has no control over purge unit operation.  Its only function is to interrupt power to the pump-out compressor motor and the isolation solenoid valve in the event excessive pump-out compressor  run time  is detected.

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