Is it OK to mix ABS pipe to B vent pipe to complete furnace venting?
ABS is allowed by some mfg for High Efficiency units. What type of unit is this. And if H.E. , did they just run the ABS through the B vent to the outside as sort of a chase.
Just saw the other foto - appears to be a H.E. Unit. Check with Carriers specs ref the use of ABS and maybe they just ran it thru the ceiling inside the bvent as not to cause ceiling damage ripping the B vent out. Where did the ABS terminate ?
It terminated through the roof vent pipe cap on top.
No. You cannot vent a condensing type furnace through B vent
Do you have a reference for that
Sure give me the make and model and I’ll dig up the installation instructions for you. Since all Cat IV appliances are listed, if you disagree, show me any installation anywhere that says you can use “B” vent with a condensing type gas fired appliance.
What do you think the corrosive condensate does as it runs down the interior of the “B” Vent, that is before it drips down through the open bottom and onto the floor below in this installation? Why do you think condensing type furnaces have condensate drains and utilize corrosion resistant vent materials of either plastic or stainless?
The first place that came up on Google: http://energy.gov/sites/prod/files/2014/10/f18/October%209th%20Workshop%20Presentation%20-%20Kevin%20Dunn.pdf
This led me to believe that the ABS vent pipe ran to the exterior, not just into the B-vent and stopped.
I was of the same opinion that the ABS did not terminate into the B-vent but just used it as a chase which should be perfectly correct. The old B-vent would actually make it a better installation because the cold attic temp would not be as condensing to the ABS as it would be just strictly exposed to the attic temps
I interpreted that it terminated within the “B” vent. On second read, I think Larry’s interpretation may be correct (the OP will need to clarify with “it” is).
If the ABS terminates within the “B” vent it’s an issue. if it goes completely through to the exterior is not, though it may be challenging to get a water tight seal. I’m curious how they achieved a water tight seal if they ran the ABS completely through the vent cap.