Index: firmware/App/Controllers/SpentChamberFill.h
===================================================================
diff -u -re6415d33321e7990c3b5e82b0c8a87c64cc3a2c8 -r667b74fa0fcd8368f83fc8f8df5166eabea2bf4b
--- firmware/App/Controllers/SpentChamberFill.h	(.../SpentChamberFill.h)	(revision e6415d33321e7990c3b5e82b0c8a87c64cc3a2c8)
+++ firmware/App/Controllers/SpentChamberFill.h	(.../SpentChamberFill.h)	(revision 667b74fa0fcd8368f83fc8f8df5166eabea2bf4b)
@@ -33,7 +33,7 @@
 
 #define FRESH_DIAL_FILL_PRESSURE_MIN_PSIG          22.0F                ///< Minimum fresh dialysate pressure (D18) limit for spent chamber fill operations.
 #define FRESH_DIAL_FILL_PRESSURE_MAX_PSIG          30.0F                ///< Maximum fresh dialysate pressure (D18) limit for spent chamber fill operations.
-#define SPENT_DIAL_FILL_PRESSURE_MIN_PSIG          24.0F                ///< Minimum spent dialysate pressure (D51) limit for spent chamber fill operations.
+#define SPENT_DIAL_FILL_PRESSURE_MIN_PSIG         -10.0F                ///< Minimum spent dialysate pressure (D51) limit for spent chamber fill operations.
 #define SPENT_DIAL_FILL_PRESSURE_MAX_PSIG          30.0F                ///< Maximum spent dialysate pressure (D51) limit for spent chamber fill operations.
 
 /// spent chamber fill data structure