new water heater venting question

sonicboomin

I'm getting my water heater replaced. i was told the hood and vent used on my unit now was small for it(3 inches).
I have a chimney with liner installed. If new heater requires 4 inch vent and the opening to my chimney is 3, will installer adjust that? is that something that is common?

Jamie Hall

Ah... depends on the chimney liner itself (not the opening in the chimney). If the chimney liner is correct as to type and size, then the installer can adjust the connections.

If it isn't... you have a big problem.

You should verify the type and size of the liner in the chimney -- you may need to have a chimney sweep to do that -- before proceeding.

sonicboomin

thanks for reply. not sure to be honest, chimney not used as fireplace as we dont have any, runs from center of house from basement to roof.
i have steam boiler and water heater connected to it from basement.

STEVEusaPA

You have both a steam boiler and a water heater connected into a 3" liner?

JUGHNE

I would guess he has a masonry chimney with a liner that is large enough now for the boiler and WH. Old WH has 3" vent, new might have 4" vent, 3" is maybe WYEd into liner......or liner is old school masonry with only a 3" hole in it.

sonicboomin

Hi no, opening for steam boiler is much larger than 3 inches.

JUGHNE

A picture showing the whole set up would clear this up.

sonicboomin

i will take pic once im home. FYI new boiler is AO smith 50 gallon 40000 btu,
anyone know if 3 inches will work for that model?

EBEBRATT-Ed

@sonicboomin

Flue pipes and liners are sized for each individual job. They are base on btu input of water heater, btu input of steam boiler and height of chimney and type and size of the existing liner

We would need all the information to do that, but that is up to your installer. 3" flue may be fine for the water heater

Larry Weingarten

Hi, I’d like to see the spec sheet for the heater. Normally 3” vent is fine for 40,000 btus.

Yours, Larry

EBEBRATT-Ed

I could be wrong but I think a natural draft water heater that normally can use a 3" vent has to be 4" under some conditions I think if vented with a draft assisted boiler

JUGHNE

Pictures??