Rusty Flue Pipe & Inspection

[hammertoe27]

Hi all, this is my first post and I'm glad to have found your site! We are in the process of buying a 42 year old home (the heating system is approximately 23 years old), and our inspector stated this in his report: "We noted rust damage/deterioration to the gas flue pipe at the roof.....We identified extensive damage to the gas flue pipe, as viewed from the attic." Our inspector, who has been in business for 20 years, said he can count on two fingers how many times he's seen the bad condition of the flue pipe in the attic. I have attached pics (I hope!), and am sorry they couldn't be more fully detailed. The sellers said that they had an HVAC guy come out to look at it and he doesn't think it's an issue, so the sellers don't want to take care of it. I'm obviously concerned for my family's safety, and am doing as much research as possible on this. What are your opinions? Thanks so much!

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[waynesoper]

stop wasting your time on the computer researching and take 300 dollars out of your pocket. Change out the deteriorated parts and protect your family.

No one's going to tell you anything different from your inspector. Believe what he said. If you want to lose the house over a few hundred dollars that's up to you.

MAbey your broker will throw in the cash to close the deal. HAHAHAHAHA ask her go ahead ask her

[randynavarro]

I see that type of deterioration every once in a while. It's not that rare. A lot of complex variables factor in to why one flue pipe will rust more than another--no matter for this discussion.

Replacing those sections is simple and should be done. That HVAC guy that said it isn't a problem needs to be thumped up side the head. It sounds like he's in the pocket of the listing agent.

When replacing, make sure the tech (or whomever) is able to investigate the rest of the flue that travels down through the house all the way to the furnace. There's likely other sections of damage but probably not as severe.

There will certainly be lots of debris and particulate inside that flue that will have fallen down to the lowest points of the run. If the other sections of pipe aren't "damaged" they'll certainly have debris that will need to be cleaned out.

This is normal fare for a reputable and honest HVAC tech.

Edit: If you're feeling particularly persnickety, have that other HVAC tech put somethig in writing stating this isn't a problem. The "he said, she said" game is the worst in a real estate transaction.

[Bill Kibbel]

It looks like a single-walled pipe in the pic, not a double-walled B-vent. That would certainly be a major cause of the rust (condensing of the exhaust). It also looks like an improper transition from oval to round pipe. It's likely the whole vent needs replacement. It's breached through in one visible location and will at many others, if not already. Condensation has also probably been draining back into the furnace/boiler as well.

Regarding the inspector, who was "we". Were there 2 inspectors, a 2-headed inspector or is the inspector suffering from dissociative identity disorder.

[hausdok]

Hi,

That oval pipe is so badly corroded and the walls are so thin that it's cracked inside the attic. If the homeowner can't see that in the picture, he's a dolt.

It certainly does look like it's single-walled vent material, in which case someone seriously screwed up way back when. because they weren't supposed to use single-walled vent material in a concealed or cold location.

Most of the byproduct of ignition is water and the rest is other junk like sulfur and nitrogen. If the vent is a single-walled vent, it allows the exhaust to cool too rapidly and those gases condense to a liquid inside the pipe. The condensate is acidic and it literally eats the vent material, and the furnace, from the inside out.

Even if it's double-walled material from the utility room up through the roof, it's possible that there is something going on at the furnace that is causing the exhaust gas to cool too rapidly and lose bouyancy. When that happens, as the gas leaves the end of the vent it's lost almost all bouyancy and it kind of settles around the end of the vent and lingers there and eats up the vent.

I see it a lot and usually when I see it I can go into the garage or the utility room, wherever the furnace is, and I'll find the connector pipe, the section of pipe from the collar of the appliance to the shared flue, is a single-walled pipe that's allowing the gas to cool before it even reaches the double-walled vent.

I think the inspector made a good call and I think that the homeowner is either flat out lying to you or the supposed HVAC guy he's dealing with is not actually an HVAC guy or is possibly just plain incompetent. You can tell 'em I said so and I'd be happy to say it to the tech's face if we were to ever meet, 'cuz he's an idiot.

That said, Wayne is right, this isn't that expensive to fix. Still, if he's willing to lie about something like this, what else is he concealing?

ONE TEAM - ONE FIGHT!!!

Mike

[Neal Lewis]

It certainly does look like it's single-walled vent material, in which case someone seriously screwed up way back when. because they weren't supposed to use single-walled vent material in a concealed or cold location.

What if the heating system is located in the attic. At 23 years old, it would be gravity vent without an inducer fan. For an older attic furnace, was standard to use a single wall exhaust vent in the attic, and transition to B vent through the roof ( at least that's what I used to see in NJ).