Index: firmware/App/Modes/ModeChemicalDisinfect.c
===================================================================
diff -u -r51d67532a86df4c88bebe57d224a9c81c029c08b -r6a4bdeb4743eab20c2eaf7bcc08738d24c830001
--- firmware/App/Modes/ModeChemicalDisinfect.c	(.../ModeChemicalDisinfect.c)	(revision 51d67532a86df4c88bebe57d224a9c81c029c08b)
+++ firmware/App/Modes/ModeChemicalDisinfect.c	(.../ModeChemicalDisinfect.c)	(revision 6a4bdeb4743eab20c2eaf7bcc08738d24c830001)
@@ -522,6 +522,7 @@
             setValveState( VPI, VALVE_STATE_CLOSED );
             setValveState( VRD1, VALVE_STATE_OPEN );
             setValveState( VPO, VALVE_STATE_FILL_C_TO_NC );
+            setValveState( VPD, VALVE_STATE_DRAIN_C_TO_NO );
             setDrainPumpTargetRPM( DRAIN_PUMP_TARGET_RPM );
 
             // Assume reservoir 1 is full and drain it