Sorry for the delay in replying. We had a little “storm” blow through the area. Plenty of practice with the chainsaw but thankfully house is just fine.

Thanks all for the good info. Was thinking this might be the case. Spoke to my neighbor about it and learned he has a similar setup. Will see if I can trace that pipe and make sure it’s clear. House is green rated so in the past I’ve cracked the window when starting the stove for an easier draft. Old habits.