I have a P38 ( same stove just man. ignition). I find if I keep the stove throttled back for a extended time I will get the creosote build up. I had the pipe catch fire and ruined ESP. I cleaned pipe, replaced ESP and started running the stove on a higher setting. No problem since. If the exhaust gas is not hot enough it condenses in the pipe and turns into black tar that will burn.
	
		
			
		
		
	
				
			 
	 
	 
 
		 
 
		