Gas Furnace vertical exhaust vent has dropped down 8 to 10 inches

moreheat99

My vertical gas furnace exhaust vent appears to have dropped down somewhere around 8 to 10 inches. In the pic that is from the top of my hot water heater you can see my gas hot water heater vent is sloping down as it connects to the furnace exhaust. And, the vent running directly off of the furnace is also sloping down before it connects to the main vertical exhaust. I'm assuming that both of those appliance vents should be sloping upwards when they connect to the main vertical exhaust. To get them to slope upwards the entire vertical exhaust vent would have to be around 8 to 10 inches higher. I have tried pushing and pulling the exhaust vent from various places ( floor level and attic level ) and it does not move.

The vertical vent travels through one floor of my house behind walls. I lowered an endoscope camera behind the wall and down the entire length of the exhaust vent and I do not see any issues with the vent behind the wall. Next, the vent enters my attic ( which is about 15 feet tall to the roof line ). I have examined all of the vent in the attic and I don't see anything obvious to account for 8 to 10 inches of vent that has dropped down.

I don't see any bracing support for this vent behind the walls or in the attic so I'm assuming the vent is supported at the roof line somehow.

I have 2 pics that show the top and bottom of a wider section that wraps around the main vent. I wasn't sure of the purpose of the wider vent and wonder if something inside of that wider section of the vent could be where the problem is at?

EBEBRATT-Ed

Can't tell but that needs to be fixed pronto. You run the risk of carbon monoxide poisioning. You should shut both appliances off and shut the gas off to both

Big Ed_4

I don't see bracing or supports either ...

109A_5

Hello @moreheat99,
Maybe if you can get behind the other thing to the left of the water heater the whole assembly could be jacked up slowly to the proper height and verified it all remains intact then secure it all so it never happens again.

Looks like this deformed and separated too as it all slid down.

moreheat99

Thanks all for comments. I do have CO alarms in home. It would take me too long to explain, but I believe this has been like this for many years now based on some other attic insulation work that was done 5 or so years ago and the location of the furnace vents. What made me notice this problem was I was replacing my hot water heater recently and noticed the down slope. I rarely go into this furnace closet in my garage so no telling how long this has been like this. I live in a small CO mountain town and have a few calls out to the furnace service companies in the area....just on their waiting list for now as they are very backed up. I was hoping to find something obvious that I could DIY fix, but I don't want to break anything. Right now I'm just perplexed on what is holding up all this vent weight ( 8 feet thru one floor of townhome and another 20+ feet in the attic). Could all of this weight be held up at the roof by some type of support from on the top of the OSB on the roof ?

mattmia2

It should have been supported somewhere but it is very possible it was only held up by the roof flashing and someone caused it to fall down while reroofing the roof or it happened by itself and it is now supported by the storm collar or the cap

JUGHNE

Can you post pictures of what and how is connected into the bottom of the tee in the basement?

Could this have started out originally with a much shorter water heater and the replacement was a lot taller?

moreheat99

When I moved in townhome it had original water heater and it was same size as the replacement.

One pic here is close up of hot water heater vent tie into the vertical exhaust. The other pic ( very hard to get a good one ) is the furnace vent tie into the vertical exhaust. Note that on the furnace vent picture I am pointing the camera directly horizontal. So you can see that the vent running directly off of the furnace would have to rise up at least 8 inches just to get perfectly horizontal.

JUGHNE

You have a serious situation there.

I wonder about the purpose of the wider section in the attic.
Perhaps it has come apart inside of that.

The slope angle in the attic looks about correct. Is that just a hole strap floating as if it was to be a support but never used?

The roof flashing usually would not hold the entire vent up.

The very bottom at the tee looks wonky, as if the inner pipe might be sliding out of the outer shell....but I am not familiar with that brand.

That floor plate might be a homemade version of the "fast vent?" which is a factory plate designed to hold B-vent piping up and provide 1" clearance and fire stopping.
The support plate I speak of has metal tab fingers that allow you you to push the pipe thru but not pull out, without considerable grief....I know this.

Any "home inspector" (if you had one, should have noticed that) maybe it has happen since you brought the place.

You certainly should not run the furnace, actually not even the water heater.

We are all anxious to see the fix for this, thank you.

HomerJSmith

I just finished re-venting a 40 yr old common vent and conductor vents for a 75K water heater and a 150K induced draft boiler. The 75K w/h was vented with the old 3" conductor vent that was connected to a 33K w/h. Says something about professionalism. Who needs the Uniform Mechanical Code!
The whole shebang was supported by the conductor vents to the common vent and the roof jack (flashing). 25' of snow caused the common vent to fall 6"-8" down. Since the roof collapsed and was re-done I supported the common vent with several lengths of plumbers tape bolted around the common vent and brought up above the roof sheathing and screwed on to the top of the roof. It could have been screwed on to the roof rafters, but the way I did it was much stronger.

The common vent NEEDS to be supported. Don't ignore this important step. The slope of the connector vents should be at least 1/4" per foot rise.

Sal Santamaura

moreheat99 said:

...I do have CO alarms in home...

If you're referring to the typical UL-rated alarms, they'll not protect you from extended, low-level CO poisoning. Only a low-level CO detector will keep you safe.

yellowdog

@HomerJSmith you have a draft induced boiler vented with a natural draft water heater into the same flue? sounds like a bad idea. what happens if the chimney plugs for some reason and the boiler starts?

moreheat99

Thanks again all for the comments and concern. I on the phone again trying to find someone who can come look at this. I will check out exactly kind of CO alarms I have in the house. Also, this is a natural gas furnace...no boiler...and the vent is not tied to a chimney....this exhaust is just for furnace and hot water heater.
I am contemplating trying to take apart that wider section of the vent as it seems it is attached with just screws, but again, I don't want to make the problem worse by breaking something. I just have no idea what the purpose is of that wider section. You can see that the main vent kinda runs into and out of that wider section. Just wondering if that is some type of joiner, etc. for two sections of vent and possibly the missing 8 inches could be accounted for behind that wider section. I have no idea...only speculation.
Thanks again all!

mattmia2

That wider section looks like it is for heat shielding to reduce clearance to combustibles.

pecmsg

moreheat99 said:

Thanks again all for the comments and concern. I on the phone again trying to find someone who can come look at this. I will check out exactly kind of CO alarms I have in the house. Also, this is a natural gas furnace...no boiler...and the vent is not tied to a chimney....this exhaust is just for furnace and hot water heater. I am contemplating trying to take apart that wider section of the vent as it seems it is attached with just screws, but again, I don't want to make the problem worse by breaking something. I just have no idea what the purpose is of that wider section. You can see that the main vent kinda runs into and out of that wider section. Just wondering if that is some type of joiner, etc. for two sections of vent and possibly the missing 8 inches could be accounted for behind that wider section. I have no idea...only speculation. Thanks again all!

I can almost guarantee you have UL Listed won’t alarm until your almost dead alarms. 

A UL listed alarm needs to exceed 70 ppm for up to three hours before it goes in to alarm!
 It can hover between 65 and 75 all day long!
OSHA only allows us 30 ppm over an eight hour workday!

HomerJSmith

yellowdog, we're all dead in the long run anyway. I guess the code writers missed that. I guess a CO monitor would allay one's fears.
PS. The same would happen with any plugged common vent, but might just happen faster with a fan assisted appliance. I have come across separated common and conductor vents, miss-sized vents, vents incorrectly sloped, but never a plugged vent. But don't worry I kept my fingers crossed when I left the job.

EdTheHeaterMan

As I look at the pictures provided, all you need to do is to remove the seal from the flashing in the attic (not the roof flashing) and then jack up (or lift up) the full length of the vertical pipe that fell when the attic insulation work was completed. Then add a better support to take the weight of the entire vertical pipe and distribute it to more than one location.

See the files below

After you lift the pipe and properly support it, you will need to check all the joints in the vent pipe top make sure that none of them are compromised.

And by the way, the aluminum tape on those joints is not necessary unless they are covering up bad connections, in which case you need to correct or replace any defective connections.

realliveplumber

yellowdog said:

@HomerJSmith you have a draft induced boiler vented with a natural draft water heater into the same flue? sounds like a bad idea. what happens if the chimney plugs for some reason and the boiler starts?

Perfectly legal to co mingle a fan and natural draft appliances.

Foil tape on flue pipe is a code violation. There is no listing on any tape for that purpose. It will get you a red tag in NJ, as it has been discussed in cont. ed classes the last couple years.

HomerJSmith

Ed, the pic I posted was to show slope. There is various ways to support the common vent. I did it the easiest way since the roof had to be replaced. It can be done like a stack clamp. I do tape all the joint on single wall. I don't tape B-vent. I do like a tight vent sys. I agree about bad connections, but I don't do that kind of work and can't live with it when I come across it. It's one of my many failings.

The 40 yr old vent had rusted out in part even tho the aluminum liner was intact. 40 yrs is long in the tooth besides the W/H 3" connector vent was way undersized for a 75K heater.
Tape on B-vent is one thing, but single wall isn't forbidden in my jurisdiction. I see it all the time. You still need three screws, tape isn't a legit connection method.

moreheat99

Ed, thanks for the plan and pictures. I did free up the attic flashing. The vent does not move at all so I'm assuming it is only secured at the roof line since I don't see any other bracing. I am going to send my endoscope down behind the wall ( on my first floor ) once again and check the entire length of pipe to make sure I'm not missing some type of brace that is behind the wall. I've already looked twice, so I'm pretty sure I'm not missing anything.

The issue I see now is that if I do jack up the entire assembly about 8 to 10 inches without loosing the roof support, then the long stretch of horizontal upward sloping pipe in the attic will loose a good bit of the upward slope. I'm going to take some measurements of that horizontal run in the attic to see how much can be lifted and still stay within the minimum upward slope requirements. Or, maybe I do what you planned: lift pipe 8 to 10 inches to fix furnace/water heater exhaust slope, add plenty support straps in the attic, and then loosen roof flashing and lift from roof to ensure attic horizontal run is still correct slope.

Or, what if I cut out a 8 to 10 inch section of vent directly underneath that horizontal run in the attic, then lift the vertical pipe that would be behind the wall to take up the cut out section and then patch it up somehow....would that be asking for trouble?

moreheat99

Thanks again for all the help. I finally got a furance service company out and we were able to lift the entire vertical pipe about 12 inches up and then put in the proper bracing. All exhaust sloping pipes now go up instead of down...which should keep me from waking up at night thinking about this problem.