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gas line in chimney w/ furnace & w/h exhaust


Doug Clark
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Question: Can plus-90 gas furnace exhaust ducts, gas water heater exhaust and yellow flex gas line run through the same chimney flue?

Situation: The home has two furnaces. The main in the basement and an auxiliary in the attic.

The main furnace (gas plus-90) and water heater (gas) are in the basement situated near the chimney. The water heater is vented into the flue as normal. The exhaust ducts for the plus-90 are typical pvc. They are routed into the flue and up the chimney and are visible protruding from the top of the chimney.

The gas service is yellow flex pipe. It runs to the main (basement) furnace, then into the flue up to the attic level where the line exits the flue to supply the upper furnace.

All entrance holes into the flue appear to be sealed adequately.

I've talked to three licensed furnace installers. One said everything is OK. The second said he'd leave everything in the flue, but he'd install a metal flue pipe for the water heater exhaust through the chimney flue. The third said under no circumstances should the supply be run with the exhaust and it absolutely must be removed from the flue.

Any help?

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Hi,

So, what you're saying is the exhaust from the water heater is surrounding and condensing all over the exhaust pipe from the furnace as well as the gas supply pipe that's feeding gas to the other furnace. Sounds to me like the second guy has the most logical solution.

OT - OF!!!

M.

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Originally posted by Doug Clark

Question: Can plus-90 gas furnace exhaust ducts, gas water heater exhaust and yellow flex gas line run through the same chimney flue?

Situation: The home has two furnaces. The main in the basement and an auxiliary in the attic.

The main furnace (gas plus-90) and water heater (gas) are in the basement situated near the chimney. The water heater is vented into the flue as normal. The exhaust ducts for the plus-90 are typical pvc. They are routed into the flue and up the chimney and are visible protruding from the top of the chimney.

The gas service is yellow flex pipe. It runs to the main (basement) furnace, then into the flue up to the attic level where the line exits the flue to supply the upper furnace.

All entrance holes into the flue appear to be sealed adequately.

I've talked to three licensed furnace installers. One said everything is OK. The second said he'd leave everything in the flue, but he'd install a metal flue pipe for the water heater exhaust through the chimney flue. The third said under no circumstances should the supply be run with the exhaust and it absolutely must be removed from the flue.

Any help?

The second one is right. Give him a biscuit. The others are idiots.

If it's a chimney, it shouldn't be used as a chase. If it's a chase, it shouldn't be used as a chimney.

BTW, this is a perfect example of the reason that home inspectors shouldn't be getting their education from tradesmen. These guys are often very ill-informed.

- Jim Katen, Oregon

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I recall reading in Code Check that gas pipes shouldn't be run in chimneys as your describe. Am I wrong?

Also, why didn't they run the furnace's PVC out the side of the home instead of running it vertically up the chimney? What happens when the PVC gets to the top? Is there another elbow and piece of PVC to allow the condensate to drip onto the roof (past the mortar cap)?

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Hi,

In this case, the masonry chimney is still being used as a chimney, which makes what Doug describes wrong. However, if a flue pipe is added to the water heater and run up through the masonry chimneystack alongside the furnace vent, as the second guy recommended to him, the masonry stack is no longer functioning as a chimney and becomes a plumbing/chimney chase. As long as the furnace is listed for a vertical vent and there's a means to collect and discard the condensate from that Cat IV vent, it shouldn't be an issue.

ONE TEAM - ONE FIGHT!!!

Mike

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  • 7 months later...

Co-combustion of sewage sludge together with coal or wood has been investigated in two circulating fluidized bed (CFB) plants, a laboratory scale plant and a pilot scale 12MWth CFB boiler, in both of which the gas residence times are comparable to those in commercial plant. The investigation focuses on emissions of harmful gases from co-combustion compared to mono-combustion in CFB and the influence of air supply.

----------------------

williamgeorge

Viral Marketing

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Originally posted by Jim Katen

[quote

BTW, this is a perfect example of the reason that home inspectors shouldn't be getting their education from tradesmen. These guys are often very ill-informed.

- Jim Katen, Oregon

Amen to that. In this modern age, an inspecting unit can Google up manufacturers' drawings and specs. Such a unit can also call a manufacturer on his cell phone while looking at the gizmo in question and get info straight from the horse's mouth. And even easier, a literate inspecting unit can find building codes on the Internet and use them at will, because they're public domain.

We shouldn't be asking tradesmen for advice. Just like we shouldn't be hiding behind the muni codes bubbas.

If we're going to be useful to customers, we've got to be smarter than the people who keep us in business by screwing things up...

WJid="blue">

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