Most older tank heaters in Orange garages are atmospherically vented. Hot exhaust rises through a draft hood on top of the tank, into a metal vent pipe and up through the roof, pulling combustion air in from the room around it. That only works if the vent is connected, sloped upward, the right size and clear, and if the room has enough air for combustion.
Power-vent and many tankless heaters use a fan to push exhaust out through a wall or roof, and some draw their combustion air from outside through a separate pipe. Each design has its own installation requirements from the manufacturer, which is why the venting often changes when a heater is replaced or converted.
Visible warning signs at the heater
- The vent pipe is disconnected, separated at a joint or sagging downhill
- Rust, scorching or melted plastic near the draft hood at the top of the tank
- Soot or black marks around the burner access door
- A yellow, lazy or lifting burner flame instead of a steady blue one
- Condensation or moisture on walls or windows near the heater
- Storage boxes or a closed door blocking the heater's air supply
Venting terms
- Draft hood
- The opening on top of an atmospheric tank where exhaust enters the vent and room air mixes in.
- Backdrafting
- Exhaust spilling into the room instead of going up the vent, often due to a blocked vent or strong exhaust fans.
- Power vent
- A heater that uses a fan to push exhaust out, usually through a side wall.
- Combustion air
- The air a gas appliance needs to burn its fuel completely.
How a plumber checks venting
- Inspect the vent path.Follows the pipe from the heater to the roof or wall for connections, slope, size and damage.
- Check the burner.Looks at flame color and stability and for signs of soot.
- Test for draft.Checks that exhaust is drawn into the vent once the heater has been running.
- Review combustion air.Confirms the space or the intake pipe provides enough air.
- Recommend fixes.Reconnecting, replacing vent sections or, on a replacement, venting matched to the new unit.
Ask when venting comes up
- Is my current vent the right type and size for this heater?
- If I replace the heater, will the venting change?
- Does venting work here need a permit from the City of Orange?
- Are there signs of backdrafting or CO spillage now?
Common questions
Can I check the vent myself?
You can look for disconnected or damaged pipe and scorch marks at the top of the tank without touching hot parts. Draft testing and repairs belong to a licensed professional.
Why does a new heater sometimes need new venting?
Different units have different exhaust temperatures, fans and clearance requirements, so the existing vent may not suit the new heater.
Does an electric water heater need venting?
No. Electric tank heaters don't burn fuel, so they have no combustion exhaust.
General information for Orange, not a quote or professional advice. In an emergency, call 911.