I have a Tjernlund SS1 powervent that is going on 9 years old, my heating guy told me, you should replace it with a chimney.  I'm wondering what brand chimney piping to use. it will be an external system- it 21 feet from the center of the powervent to the roofline.  I have to offset to get past the soffit. any guidance would be appreciated.
Greg
	
		
			
		
		
	
				
			Greg