I hooked up my stove ran dry for 20 minutes got the E-2 message, filled the hopper with pellets. Hit  the on button once got the S U message then after 20 minutes got the E-2 message and unit stopped.  Started again and again and it still runs for 20 minutes with the S U message and then give the E-2 message and shuts down.  Does anyone know what's wrong.  Thanks.
	
		
			
		
		
	
				
			
	
	