does my chimney need a liner?

amakarevic

i plan to use my chimney to exhaust a gas water heater with a 3" duct and a radiator boiler with a 6" duct. there is no soot involved, i.e. only gas burning fumes. my questions are:

1. can i just run the ducts to an unlined brick chimney or do i have to have a liner inside?

2. regardless of the answer to 1., can entry points of the two ducts at the bottom of the chimney be at the same horizontal level or do they need to be one above the other?

thanks

yuri

You need a liner or the fumes will eat the mortar out between the bricks and it will collapse. Water heater needs to enter above the entry point of the boiler.

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gregzoll

I would just go direct vent. There are kits to retrofit non-direct type water heaters. Would be the best way.

amakarevic

what's a direct vent?

hvac5646

hi, Yuri!

We use liners every job and we use a smoke pipe of B-vent Wye

like this

How are you running liners?

hvac5646

It a two PVC pipes system that exhausts out the side wall.

And takes air in to burn the gas.

So you got a system that sucks and blows. Happy ending

amakarevic

not sure i wanna drill another couple holes in my wall. will just probably get a liner. where do you buy they and are they just regular ducts? maybe Roof Center?

yuri

We get a Pro chimney company to do ours. They bust the base open and install a cleanout and one entry for the furnace and another above it for the water heater. Must be B vent or 2 single wall liners( one inside the other here).

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yuri

Must be aluminum or stainless steel non corrosive liner and B vent/ 2 layers thick where I am and sized according to the amount of BTU's of both appliances and the height of the roof/rise and according to the gas code. May want to get a Pro chimney company to do it. If not done properly you can get downdrafts/fumes spilling and pressure switch tripping problems with the furnace.

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amakarevic

i just measured inside the chimney shaft and i will need a 6" liner. will that be enough to support a 6" duct from the boiler and a 3" one from the water heater?

yuri

Depends on these factors, add the input BTUs from both from the rating plates. Not sure about the code requirements in your area.

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amakarevic

this is what i've found:

http://www.efireplacestore.com/cpf-68218.html

however, the next question is what type of fittings do i need to terminate both ends of the chimney.

on the inside end, i will need one 6" elbow at the very bottom, for the boiler, and a 6x6x3" tee right above it for the 3" water heater duct. also, will i need anything on the chimney top?

i saw they have many different types of fittings on that web site and i am unsure as to which to get.

also, for the duct inside the house for in between the appliances and the chimney entry, can i just use regular hard duct from home depot? i noticed that the existing 6" duct for the boiler in the basement has firmer joints than regular crimped/taped ones for like a dryer vent and they have screws.