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Too many elbows


randynavarro
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Saw this in a brand new home today. I know in my gut this vent configuration is incorrect but I can't find anything in writing to back it up.

My view is a) too many 90 deg. elbows b) connection from the water heater should be as high to the garage ceiling as possible.

Any references or thoughts?

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Furnace and water heater are not installed in a "workman like manner".

Flues should be reconfigured by a qualied HVAC technician.

If the guy tried to do that at my house it would have been reconfigured before he left and not assembled with pieces that were chosen based on what's on the truck.

I'd move the water heater to the right of the furnace and neaten that mess up.

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Randy must of thought I was looking for modern art and not poets!

There must be $100 bucks for material where $18 would have done it. Have licensed tradesperson check it out. In 4.3yrs when the present buyer moves, the issue will come up again. Better to fix it now. Just my opinion.

Did anyone check Mike's math?

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Originally posted by hausdok

Hi Randy,

OK, I'm definitely the weakest link when it comes to math, so someone better check this. It looks like there is an adapter at the furnace collar and that they've used a larger connector up to the ceiling and that the vent above the wye where the water heater joins also steps up. Looks like the collar and the water heater are 4" and the big connector is 5" so I'm presuming the flue is 6".

Using that 50% rule, I'm coming up with a minimum required flue size of 25.905 sq. inches. If the flue is a 6" pipe, that's 28.26 sq. in.. If minimum flue size must be increased an additional 30% to make up for the loss in capacity of 10% per additional 90 degree bend, that's an additional 7.7715 sq inches or a total of 33.6765 sq. inches, which means that 6" pipe falls short of what's needed. However, if that's a 7" flue, it's 38.465 sq. inches and would be okay.

ONE TEAM - ONE FIGHT!!!

Mike

Thanks Mike. I'll check it when I'm done posting (i'll have to get my abacus out of the attic)

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Originally posted by Les

Randy must of thought I was looking for modern art and not poets!

There must be $100 bucks for material where $18 would have done it. Have licensed tradesperson check it out. In 4.3yrs when the present buyer moves, the issue will come up again. Better to fix it now. Just my opinion.

Did anyone check Mike's math?

I agree Les. All's they had to do was go right off the top of the furnace with a 45 elbow, then 45 up to the ceiling. The water heater could then tie in close to the ceiling. Is that what you mean by $18?

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Originally posted by chrisprickett

Can't tell the brand of vent from the pic, but here's Amerivents installation instructions:

Download Attachment: icon_adobe.gif Ameri-Vent.pdf

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Thanks Chris. I'll read when I'm done here. Regardless, my experience has been that gas venting can be really complicated and almost borders on rocket science. What's gotten me by for so long without gettin' in trouble, is that water heater and furnace configurations in garage are very common here. Usually everything vented the same. It takes something like this to make you scratch your head and wonder.

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I'm spoiled and very blessed down here. I have yet to see one single example of venting two appliances into one pipe, or even one appliance into a chimney. They all go up and out through the roof, solo, every time.

God help me if I ever run into something really complicated.

Kick 'em in the shins Randy!

Brian G.

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Originally posted by hausdok

Thanks Chris. I'll read when I'm done here. Regardless, my experience has been that gas venting can be really complicated and almost borders on rocket science.
Yeah, I used to think that until I read this: JLC Article on Venting Gas Appliances

ONE TEAM - ONE FIGHT!!!

Mike

Mike, great article, but here's a quote right from him. Even he is saying that its pretty complicated.

Complex Range of Options

There's a wide range of choice in appliances and vents. But for every combination of equipment type and vent material, the basic goals and limits apply: The vent must be able to provide sufficient draft for the equipment; it must be warm and dry enough to avoid damaging corrosion; and it must be fire safe. The sizing tables and other venting rules aim to achieve that safety and durability, but in providing for the whole range of choices, the rules have become complicated.

This is the only thing he says about elbows.

However, it's important to realize that the tables don't account for every possibility. They don't include the effect of elbows in the system, for example: Each table assumes no more than two 90-degree bends, and vent capacity is reduced by 10% for each additional 90.

Well, now i'm just copy/pasting the article - anyone can read it for themselves if they want.

I guess I'm thinking that even if a guy had all the tables and cross-references that are mentioned, doing all the calculations and measurements is too technically exhaustive and outside the scope of a normal home inspection - isn't it?

Which brings me back to my original concern - my gut says its wrong - its gotta be wrong but I can't prove it. You know as well as I do the HVAC "professional" hasn't performed any calcs. The client would have to pay lots o' dough to get an "expert" in just to calc this one vent issue - is it worth it?

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Originally posted by hausdok

Your absolutely right,

Whether you client opts to pay for it or forces it to be on the seller's nickel isn't your concern and should not be. Just report what you know. If you're not sure say so. But for gosh sakes don't go getting involved in who pays for what. That's not our concern. Our job is to report, not to hold hands. They pay their realtor to do the hand holding.

ONE TEAM - ONE FIGHT!!!

Mike

Totally agree . . .but I guess I'll 'fess up now.

This entire 'inspection' was for a friend. I told her I would help her out as a favor. On top of that, she IS a realtor. No worries, we were friends first, then she became a realtor. No report, no paperwork, no fuss, right?!! So basically she is telling the builder what to fix without paperwork or a report. So as a friend, I'm obligated to hold her hand a bit cuz she doesn't have a realtor!

Maybe the line between friend and business should be discussed in another thread![:-headach

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I don't have any facts but I'll look to see if theres any thing different than what's been posted. It seem from reading the replies that allowance for 90's is a little vague.

Here's what I know from the field. A little town just west of here is one of the toughest in the country. I've heard of restaurants who have built all over the country, come to this town and say they have never seen more strict code inforcement.

Flu pipes in this area were allowed 25' for a straight run. Take off 5' for each 90, 2.5' for each 45.

I know I may get scolded for this but the pipe job, aside from a lot of joints, looks very good to me. If you have ever installed a double wall flu pipe, you know that all of the pieces must be an exact fit with no cutting.

It looks to me like these guys took care to fit every peice. They even took care to include a "Y" to tie in the water heater instead of a "T". I agree with Chad on this to a degree, the water heater could be moved and the flu could be run differently and it may still have too many turns. But a shotty job I disagree.

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I'm gonna put my foot in it. I agree, too many 90s from what I read and see, could have been done a little cleaner. How come nobody mentioned that the Hot water expansion tank was mounted horizontally? Every one I have installed is vertical. Is there one with the bladder sideways?

Wipes off shoes,

Ron

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Originally posted by kevin846

I don't have any facts but I'll look to see if theres any thing different than what's been posted. It seem from reading the replies that allowance for 90's is a little vague.

Here's what I know from the field. A little town just west of here is one of the toughest in the country. I've heard of restaurants who have built all over the country, come to this town and say they have never seen more strict code inforcement.

Flu pipes in this area were allowed 25' for a straight run. Take off 5' for each 90, 2.5' for each 45.

I know I may get scolded for this but the pipe job, aside from a lot of joints, looks very good to me. If you have ever installed a double wall flu pipe, you know that all of the pieces must be an exact fit with no cutting.

It looks to me like these guys took care to fit every peice. They even took care to include a "Y" to tie in the water heater instead of a "T". I agree with Chad on this to a degree, the water heater could be moved and the flu could be run differently and it may still have too many turns. But a shotty job I disagree.

Kevin, its good to know you have some pretty clear guidelines in your area. That makes is easy for all involved.

I also don't think the work was 'shoddy' but more careless. Maybe careless = shoddy.

Look at the picture again - all the HVAC guy had to do was 45 right off the top of the furnace to the right, line up under the ceiling stack, add another 45, then run straight up to the fitting in the ceiling. Then add a wye to receive the water heater and its done!! This way also allows the water heater vent to tie in as high as possible to the ceiling which IS specified in Code Check.

Simply looks 'rookie' to me.

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Originally posted by Renron

I'm gonna put my foot in it. I agree, too many 90s from what I read and see, could have been done a little cleaner. How come nobody mentioned that the Hot water expansion tank was mounted horizontally? Every one I have installed is vertical. Is there one with the bladder sideways?

Wipes off shoes,

Ron

What Mike says - they're upright, sideways and upside down here - whatever it takes to make it fit.

It is much easier, though to properly support the hanging tank when it is sideways - think about it - easy to wrap the plumbers tape around the tank and secure to the wall. Can't get a good wrap around the tank when its upright (or upside down). I call "inadequate support" a lot on unsupported expansion tanks.

Good thought though - maybe worth a little bit of research of the mfg's specs to make sure it can be mounted in any position - just cuz everybody's doing it all different ways doesn't make it right!

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Thread stealer here.

It was my understanding that the air valve is used to compensate for the pressure difference. Has anyone taken one apart to see if it is a bladder or a separation? Difference being a separation is attached to the walls of the tank and bladder is a free floater. If it is a free floater I cannot see and reason why you could not mount it anyway you want. Here, I've only seen them mounted vertically. i'll see if I can find the mounting manual for mine.

Ron

learnin' all the time here :~)

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Randy, I knew I'd get scolded.

I looked back at the picture and tried to figure out why they at least two more elbows than they needed. The job may not be right, but I believe they may have been trying to leave access to the evaporator. Otherwise the two extra wouldn't make sense. Careless, I could go along with that.

In the city I'm based in, I preform new construction inspections all the time. 15 miles west, I never have, the guys over there are on the ball, and it does make it nice for all parties. I would not hesitate to build over there. The town by the way, is North Augusta, just accross the river from Augusta GA.

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