diff --git a/inferium-harvester.lua b/inferium-harvester.lua
index abb6c28..256bec2 100644
--- a/inferium-harvester.lua
+++ b/inferium-harvester.lua
@@ -1,21 +1,16 @@
 local config = {
-  length = 8
+  length = 8,
   firstCropZ = 2
 }
 
 local MIN_FUEL_NEEDED = (10 + config.firstCropZ + config.length) * 2
 
-local VERSION = "0.1.0"
+local VERSION = "0.1.1"
 local IDLE_TIME = 2
 
 local turtleUtils = require('libs/turtle-utils')
 
 -- UTILS
-local function waitForMatureCrop()
-  return turtleUtils.waitFor(function()
-    return turtleUtils.isMatureCrop(turtle.inspectDown)
-  end, IDLE_TIME)
-end
 
 local function assertEnoughFuel()
   if turtle.getFuelLevel() < MIN_FUEL_NEEDED then
@@ -95,8 +90,14 @@ end
 
 local function refuelProcedure()
   turtle.turnLeft()
-  turtleUtils.waitForInventory('front')
-  turtleUtils.refuel(MIN_FUEL_NEEDED, turtle.suck)
+  turtleUtils.waitForInventory('front', IDLE_TIME)
+
+  local refuelOk, refuelErr = turtleUtils.refuel(MIN_FUEL_NEEDED, turtle.suck, IDLE_TIME)
+
+  if not refuelOk then
+    error('Cannot refuel the turtle: "' .. refuelErr .. '"')
+  end
+
   turtle.turnLeft()
 end
 
@@ -113,7 +114,7 @@ local function goBackToHome()
 end
 
 local function harvestDown()
-  local cropName = waitForMatureCrop()
+  local cropName = turtleUtils.waitForMatureCrop(turtle.inspectDown, IDLE_TIME)
 
   if not turtle.digDown() then
     error('turtle cannot harvest crop')
diff --git a/libs/turtle-utils.lua b/libs/turtle-utils.lua
index 5284d10..00ad00f 100644
--- a/libs/turtle-utils.lua
+++ b/libs/turtle-utils.lua
@@ -6,14 +6,14 @@ turtleUtils.getInventory = function(side)
   side = side or 'front'
   local inv = peripheral.wrap(side)
 
-  if peripheral.hasType(inv, 'inventory') then
+  if inv and peripheral.hasType(inv, 'inventory') then
     return inv
   end
 
   return nil
 end
 
-function waitFor(predicate, sleepTime)
+local function waitFor(predicate, sleepTime)
   sleepTime = sleepTime or DEFAULT_IDLE_TIME
 
   while true do
@@ -33,6 +33,14 @@ turtleUtils.waitForInventory = function(side, sleepTime)
   end, sleepTime)
 end
 
+turtleUtils.waitForMatureCrop = function(inspectFn, sleepTime)
+  inspectFn = inspectFn or turtle.inspect
+
+  return waitFor(function()
+    return turtleUtils.isMatureCrop(inspectFn)
+  end, sleepTime)
+end
+
 turtleUtils.trySuck = function(suckFn, sleepTime)
   suckFn = suckFn or turtle.suck
   sleepTime = sleepTime or DEFAULT_IDLE_TIME
@@ -151,20 +159,25 @@ turtleUtils.selectItemByName = function(itemName)
   return false
 end
 
-turtleUtils.refuel = function(minFuel, suckFn)
+turtleUtils.refuel = function(minFuel, suckFn, sleepTime)
   suckFn = suckFn or turtle.suck
+  sleepTime = sleepTime or DEFAULT_IDLE_TIME
 
   if not turtleUtils.selectFirstEmptySlot() then
-    return false
+    return false, 'turtle inventory is full'
   end
 
   while turtle.getFuelLevel() < minFuel do
-    suckFn()
+    local suckRes = suckFn()
 
-    local ok = turtle.refuel()
+    if suckRes then
+      local ok = turtle.refuel()
 
-    if not ok then
-      return false
+      if not ok then
+        return false, 'selected item is not considered as fuel'
+      end
+    else
+      os.sleep(sleepTime)
     end
   end