High efficiency furnace question

Hi everyone I’m a new inspector waiting for my licence to be issued but meantime just finishing up my last contracting job. The client is selling and we were talking about his furnace which he said it was a high efficiency model. He said the guys who fitted it said it was (sounds dodgy) but I noticed it had standard metal flue pipe entering into a vertical b vent but the unit looked newer and had a sealed bottom compartment with a spyglass viewer. I thought high efficiency’s used plastic 686 pipe and vented horizontally outside. Is it high efficiency or installed wrong and how do I tell? Thx Howard Britannia home inspections

Check manufacturers specification.

Look up the model number

Howard, two words for you to start. Internet and research. We all do it and it is amazing what information is out there and available. In my brief look on the internet I came up with several sites. But direct venting (plastic 686 piping) high efficiency condensate furnaces are the only ones I have seen. None of them that I have ever come across need B-vent chimneys.

Thanks George that’s what I was thinking just didn’t seem right not sure who installed it!

HE furnace will corrode that inner aluminum wall in typical b-vent flue, that’s why PVC is used instead. Some installers may not know this and install b-vent or reuse existing b-vent, check the model like others suggested. If there is a condensate line/pump, that is your first external clue. All HE units will have one, AFAIK, to remove the condensate from the unit.

Ok thx I’ll investigate it for him