How to find replacement parts for a rusted water heater vent pipe
Rust on a water heater or boiler exhaust pipe can usually be fixed by replacing just the damaged vent sections rather than the entire appliance. The main difficulty is identifying the correct name and part for the pipe running from the unit up through the roof so you can swap out the rusted components safely.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 11.7× more often in r/hvacadvice than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Applying duct tape to the damaged ventDid this help you?
- 2Trying to identify the part as a wye, 90-degree bend, or adapterDid this help you?
- 3Replacing just the corroded pipe rather than the entire heating unitDid this help you?
- 4Call a professional to properly slope and glue the exhaust pipesDid this help you?
- 5Clean, prime, and glue the pipesDid this help you?
- 6Switching to an electric water heater instead of dealing with the ventingDid this help you?
- 7Getting a second opinion from another plumberDid this help you?
- 8Checking if another brand of water heater allows reusing or adapting the existing vent materialDid this help you?
- 9Running the vent in a different direction to avoid the finished areaDid this help you?
- 10Letting the joint dry and smearing extra glue or PVC cement on itDid this help you?
- 11Cutting out and replacing the leaking fitting with a couplingDid this help you?
- 12Replacing the ABS or PVC pipe section entirely instead of dabbing glue on itDid this help you?
- 13Separating the lowest siding panel to access the j-channel and remove the entire ventDid this help you?
- 14Pops off the white grille part from the frame using a flathead screwdriver by pressing the tabs on the sideDid this help you?
- 15Using flexible dryer vents (not approved for water heater use) to bridge the gap due to easier installationDid this help you?
- 16Hiring a licensed plumber or gas fitter to hook it up and test the draftDid this help you?
- 17buying a new vent cover and transferring just the new louvers to the old installed frameDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“The problem is that the existing black ABS exhaust vent runs from the utility room into the ceiling above the finished portion of our basement.”source ↗
“Unless I remove Sheetrock to expose the entire run, Lowe’s says my only practical option is switching to an electric water heater.”source ↗
“I really don’t want to tear apart a finished ceiling for a water-heater replacement.”source ↗
“I have a boiler furnace and the main pipe coming out of the unit is rusting.”source ↗
“Can this pipe be replaced or will the whole unit need replaced?”source ↗
“It started to get cold here and our gas heater kicked in. Never seen this leak before. The pipe is venting out.”source ↗
“Also a new error message popped up in our ecobee " Thermostat frequently rebooting" dont know if both are related.”source ↗
“How can i fix the leak??”source ↗
“Do I just need to replace the exhaust fan? There is also a condensation leak”source ↗
“It is leaking in the pvc exhaust pipe right after it exits the furnace to the right.”source ↗
“dryer vent clogged up, cleaned it nicely, noticed the louvers snapped.. k I tried to pull on it after removing the 4 outside screws, I don’t feel like going into the basement and taking apart the duct work/ insulation that wraps the duct..”source ↗
“can I bust the two inside screws off and pull the plastic cover out n just put a new one? Or will it lose its circular shape .. first time here in this situation .”source ↗
“It's for my water heater exhaust. It's the bottom end of my vent that goes straight up through the roof”source ↗
“Yeah every store here only got 3 louvers . For a 4 inch .”source ↗
“How do I replace the screen that goes over this exhaust outlet? Do I need to remove all of the siding or can the white part pop out? I started removing the screens and can see that it’ll pull out but want to check before I keep going”source ↗
“can't believe the previous owner just left it like that, that's a carbon monoxide roulette waiting to happen”source ↗
“What vent piece can I use to connect this correctly?”source ↗
Where this came up
People with this problem also raised
- 3How to replace a roof pipe boot with a cap
- 4Why does a new furnace heat exchanger fail after 3 years?
- 2What replacement material should I use for a corroded pipe nipple?
- 7Can I replace a hot water heater with a direct swap if ports match?
- 5Where to cut a cramped water heater cold line?
- 4How do I replace a dryer vent cover with weird dimensions?