Sorry what you are looking at is a hot water heater vent that is 3" and runs 15’ to the chimney flue. Doesn’t this seem to long? No back drafting was evident at time of operation.
also saw this. this is a 5" single wall smoke pipe to chimney flue, do you see the the screen on the tee portion of the pipe? This is a naturaql gas furnace and this seems to be acting like a damper to prevent negitive draft for combustion gases. I don’t know what this is and if is proper???
All looks questionable to me and would require further evaluation and necessary repairs/upgrades by quailified HVAC tech.
If it is 15’ long, it needs about 4" total horizontal rise, and the top of the chimney would have to be 20’ above where the connector enters the chimney. Per NFPA 211. http://www.nfpa.org/freecodes/free_access_document.asp
Is the natural gas draft induced or natural draft? Is their a draft diverter on the furnace? Yes then this tee needs to be removed. If no then screen needs to be removed as that is the draft diverter. Screening the diverter will cause the flames to lift off the burners and pilot assembly during high draft conditions.
It is natural draft, and this pic shows it has a heatilator on the smoke pipe. What this is doing is taking the exshaust flue gas heat through a exchanger and a mini blower fan blows the warm air into the basement for additional heat. So way is that screen tee in last pic required if so???
That’s a draft hood that the heatilator is attached to. No the draft hood tee is not needed and is actually double drafting the furnace and is most likely causing spillage at the furnace’s draft hood at times. Write it up for an HVAC Compnay evaluation.