flue pipe mystery

zepfan

looked at a job today were we would be installing a new 80% furnace.the existing flue riser while it is of ample size (6") it does not appear to be standard double wall b vent.this is a pipe that is metal on the inside an outside has a thick almost plaster material.does anyone know if there is a way to connect b vent to this? or is the only alternative to install a liner,because i will also need to connect the water heater,were someone has just stubbed single wall pipe into it,and sealed it with tape any suggestions would be much appreciated.i have attached a picture thank you

furnacefigher15

I think

That is all fuel pipe, or other low clearance rated vent material.



The inside diameter of that pipe may only be 4 or 5 inch.



If you can get the correct size liner through the existing flue, do that.



If not it might be easier to start over, the low clearance / all fuel vent materials are very expensive, and must be matched to the original in order to maintain the listings, and approvals of the various agencies.

VictoriaEnergy

Old 'A' vent

It is an older style of A vent, originally designed for venting oil appliances, the uppert tee looks like an old Selkirk Metalbestos style and the lower tee is a subsequent replacment, much newer, different brand.  Certification was toasted when the tee was changed.



A lot of these old vents had corrosion issues due to the stainless inner liner and galv coupler and outer jacket.  It should be viewed as suspect due to it's age.

zepfan

asbestos?

the i.d. of this vent is right at 6",and the size liner we would need for 106,000 btu's is five inch, so we should be able to install a new liner if we do the job.do anyone know if this existing flue contained asbestos? thank you so much for your help with this matter.