diff --git a/src/main/java/tconstruct/smeltery/logic/SmelteryDrainLogic.java b/src/main/java/tconstruct/smeltery/logic/SmelteryDrainLogic.java
index 0c5d80c2f8f..344899c67fc 100644
--- a/src/main/java/tconstruct/smeltery/logic/SmelteryDrainLogic.java
+++ b/src/main/java/tconstruct/smeltery/logic/SmelteryDrainLogic.java
@@ -186,6 +186,9 @@ public void onDataPacket (NetworkManager net, S35PacketUpdateTileEntity packet)
     public int comparatorStrength ()
     {
         CoordTuple master = this.getMasterPosition();
+        // invalid smeltery
+        if(master == null)
+            return 0;
         SmelteryLogic smeltery = (SmelteryLogic) worldObj.getTileEntity(master.x, master.y, master.z);
         return 15 * smeltery.currentLiquid / smeltery.maxLiquid;
     }