Fixed error when saving with empty conduits

core/src/io/anuke/mindustry/world/blocks/types/Conduit.java

@@ -106,13 +106,14 @@ public class Conduit extends Block{
 		
 		@Override
 		public void write(DataOutputStream stream) throws IOException{
-			stream.writeByte(liquid.ordinal());
+			stream.writeByte(liquid == null ? -1 : liquid.ordinal());
 			stream.writeByte((byte)(liquidAmount));
 		}
 		
 		@Override
 		public void read(DataInputStream stream) throws IOException{
-			liquid = Liquid.values()[stream.readByte()];
+			byte ordinal = stream.readByte();
+			liquid = ordinal == -1 ? null : Liquid.values()[ordinal];
 			liquidAmount = stream.readByte();
 		}
 	}

core/src/io/anuke/mindustry/world/blocks/types/Pump.java

@@ -2,6 +2,7 @@ package io.anuke.mindustry.world.blocks.types;
 
 import io.anuke.mindustry.resource.Liquid;
 import io.anuke.mindustry.world.Tile;
+import io.anuke.mindustry.world.blocks.Blocks;
 import io.anuke.ucore.core.Draw;
 import io.anuke.ucore.core.Timers;
 
@@ -32,7 +33,8 @@ public class Pump extends Conduit{
 	public void update(Tile tile){
 		ConduitEntity entity = tile.entity();
 		
-		if(Timers.get(tile, "pump", 8) && entity.liquidAmount < liquidCapacity){
+		if(tile.floor() == Blocks.water &&
+				Timers.get(tile, "pump", 8) && entity.liquidAmount < liquidCapacity){
 			entity.liquid = Liquid.water;
 			entity.liquidAmount += pumpspeed;
 		}