Noisy Gas Boiler venting

[rbunce]

We installed a 90% efficient gas boiler, and had it vented through the wall near the unit. The rush of air through the intake pipe especially, is so loud that it is disturbing to the neighbors whose house is only 20 feet from ours. I am re-thinking running the vent and intake pipes up the chimney that I decided not to do because of the lining of the chimney, that would have been required by code in our town, was so expensive ($1200). Now I'm hearing that we might not have to line the chimney because our exhaust gases are cool, and PVC to the top of the chimney would be OK. Would we have any trouble with condensation freezing and obstructing the pipe? How do we end the pipes at the top of the chimney (maybe with a concentric vent?) which would be right next to the top of the flu for our fireplace?

[paul52446m]

We installed a 90% efficient gas boiler, and had it vented through the wall near the unit. The rush of air through the intake pipe especially, is so loud that it is disturbing to the neighbors whose house is only 20 feet from ours. I am re-thinking running the vent and intake pipes up the chimney that I decided not to do because of the lining of the chimney, that would have been required by code in our town, was so expensive ($1200). Now I'm hearing that we might not have to line the chimney because our exhaust gases are cool, and PVC to the top of the chimney would be OK. Would we have any trouble with condensation freezing and obstructing the pipe? How do we end the pipes at the top of the chimney (maybe with a concentric vent?) which would be right next to the top of the flu for our fireplace?

If your boiler vents out in pvc pipe. and there is no other venting being put in that chimney, then you can run your intake and exhaust up the chimney both in pvc pipe with no liner.

If you have a fireplace flue real close then you can not have you boiler intake
right beside it, because the boiler intake will get bad air going to it from the fireplace. The boiler will start burning yellow and making soot, and plug up the boiler. If you chimney goes through the attic where you can get to it, then you could run both intake and exhaust up the old chimney. Cut a hole in the chimney in the attic and put the intake into the attic. then run the exhaust up the chimney through a metal top to the outside.
if the chimney is a indoor chimney then i don't think you would have any trouble with condensation freezing. later Paul

[rbunce]

Thanks, Paul. Being that the fireplace flu and the old oil furnace flu through which I was hoping to run the intake and exhaust pipes for our new gas boiler are so close at the top of the chimney, I can't have the intake there unless we don't use the fireplace. I could run the exhaust pipe up the chimney, but it is on the outside of the house so freezing condensation might be a problem. Maybe it has to be as it is, and I can hope to find some sound baffeling device for the intake pipe. You'd think the manufacturer would come up with something.