Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this problem?

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iamblessed
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Location: St. Louis

Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this problem?

Post by iamblessed »

I did not get flumes from the old tank. The only difference is the new tank is about 10 inches shorter. I only added one piece of vent pipe to it (closest to the tank) the rest of the pipe was already there. I have the windows open for safety but want to fix this problem. Here are some pictures I took. Does anything stand out as being wrong?
https://imgur.com/a/4L2L63H
https://imgur.com/a/0vHItCv
https://imgur.com/a/ArIObB3
https://imgur.com/a/J0Oa1iW
Last edited by iamblessed on Tue May 14, 2024 2:00 pm, edited 1 time in total.
bbqguru
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by bbqguru »

How long has the new water heater been installed and burning?

If it's not been very long, you may be getting the fumes from the oils and other materials from the heater itself and the new piece of vent. This should go away after a few hours of burning.
niagara_guy
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by niagara_guy »

These fumes contain carbon monoxide (CO) which can kill you and your family quickly. Nothing to mess around with. Turn the heater off and call a professional.
TT
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by TT »

Have you tested the flue temperature?
If this gas heater is considerably more efficient you will have lower flue temps which
slows down the natural thermal draft.
You also have 4-5 elbows which creates resistance that also slows down draft.
Picture # 3 appears to be a combustible material wall - wood? If it is depending on the code in your area
single wall metal venting must have 3-6” clearance to combustible materials.
Double wall B-vent material must have 1” clearance to combustible materials.
Also, putting a thin metal shield behind the pipe in direct contact of the wall does not provide
any heat resistance. There must be a dead air space between a heat shield and a combustible material with air circulation.
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bradinsky
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by bradinsky »

I’ve done a few water heaters & your set up looks scary. The venting looks dangerous. Where does the pipe you’re trying to vent into come from? Is there another exhaust generating unit before the water heater?
Topic Author
iamblessed
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by iamblessed »

TT wrote: Tue May 14, 2024 2:04 pm Have you tested the flue temperature?
If this gas heater is considerably more efficient you will have lower flue temps which
slows down the natural thermal draft.
You also have 4-5 elbows which creates resistance that also slows down draft.
Picture # 3 appears to be a combustible material wall - wood? If it is depending on the code in your area
single wall metal venting must have 3-6” clearance to combustible materials.
Double wall B-vent material must have 1” clearance to combustible materials.
Also, putting a thin metal shield behind the pipe in direct contact of the wall does not provide
any heat resistance. There must be a dead air space between a heat shield and a combustible material with air circulation.
The old water heater was 36 years old. So I am guessing it burned hotter. If I moved the tank I could replace two elbow with one 45 elbow which would help. I need to test the flue temperature. I have check the flue pipe for pitch and they are fine.
Last edited by iamblessed on Tue May 14, 2024 2:33 pm, edited 1 time in total.
Topic Author
iamblessed
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by iamblessed »

bradinsky wrote: Tue May 14, 2024 2:16 pm I’ve done a few water heaters & your set up looks scary. The venting looks dangerous. Where does the pipe you’re trying to vent into come from? Is there another exhaust generating unit before the water heater?
Yes it is a gas space heater that is off 99% of the time.
adamthesmythe
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by adamthesmythe »

I assume there is code that requires you do arrange the venting in particular ways. I don't know code, but just based on physics grounds I don't like it.

When both exhausts are active there is an excellent chance of venting into the room. If nothing else the right-angle bend that the water heater exhaust must take would produce significant back-pressure. And there is no solid connection between the water heater and the exhaust, just a cone open to the room. I even wonder if the other exhaust is OK as currently built.

I don't know how to do it right which is why I don't install furnaces or water heaters.
Last edited by adamthesmythe on Tue May 14, 2024 2:51 pm, edited 1 time in total.
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dratkinson
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by dratkinson »

If the WH was installed by an older, licensed plumber, then the work is probably to code, so is okay. Meaning the smell may be just the "new" burning off of the new WH.



But if you did the work---replaced what was there---then you may have missed something. Maybe want to have an older, experienced licensed plumber double-check your work.

Example. If the new WH has a faster recovery rate/burns more NG than replaced WH, then exhaust flue/diverter may be undersized to handle both your heater and new WH at same time.

I ran into a similar problem. Wanted to install a (3) backup heat source (non-electric, room combustion air, vented heater) to flue servicing existing (1) central heater and (2) WH. City's code compliance folks said my flue was too small. My argument that I'd only use backup heater if power was out (central heater inoperative) did not fly; they said the next homeowner might try to use all 3 appliances at same time and cause exhaust fumes/CO to spill/leak into the home.



How do fumes leak into home? There is a gap/space between the top of your WH and flue draft diverter connection. If all the fumes can't travel up the flue, then some/CO could spill out at the gap.

Search flue draft diverter: https://www.google.com/search?&q=flue+d ... rter&udm=2



Idea: CYA. Put a CO detector near/above (warm exhaust air rises) your new WH. If it remains silent, then you’re probably OK and just smell the new burning off.

If it alarms, then call a licensed plumber to fix your problem. If a young guy installed your WH, then you want an older, experienced licensed plumber to find/fix your problem.



(Updated) Idea: test. With one, then both your new WH and heater ON/firing:

Test#1 with only WH ON/firing, heater cold. Do you feel a slight draft as air flows INTO the gap/flue above your new WH? (Is a candle/match flame/smoke held near gap, pulled into flue?)
--Yes. Expected.
--No. BAD. May indicate a problem with insufficient draft.

Test#2, with both WH and heater ON/firing. Do you feel a slight draft as air flows INTO the gap/flue above your new WH? (Is a candle/match flame/smoke held near gap, pulled into flue?)
--Yes. Expected.
--No. BAD. May indicate a problem with insufficient draft.

If you find a problem, then call an older, experienced, licensed plumber to diagnose/fix your problem.



Idea. You may be getting occasional external wind gusts blowing down your flue causing exhaust to back into the house.
Search flue wind diverter: https://www.google.com/search?&q=flue+w ... rter&udm=2
Search flue draft regulator: https://www.google.com/search?&q=flue+d ... ator&udm=2

An older, experienced, licensed plumber should be able to diagnose/fix your problem. (This wind gust problem would seem more difficult to diagnose on a calm day.)
Last edited by dratkinson on Tue May 14, 2024 7:03 pm, edited 1 time in total.
d.r.a., not dr.a. | I'm a novice investor; you are forewarned.
TT
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by TT »

iamblessed wrote: Tue May 14, 2024 2:29 pm
bradinsky wrote: Tue May 14, 2024 2:16 pm I’ve done a few water heaters & your set up looks scary. The venting looks dangerous. Where does the pipe you’re trying to vent into come from? Is there another exhaust generating unit before the water heater?
Yes it is a gas space heater that is off 99% of the time.
When running an efficient gas appliance with low flue temps and moisture and only one is running it may force exhaust fumes into your unused space heater and that could be your issue.
My advice is to shut this heater down and contact a licensed professional.
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cmr79
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by cmr79 »

I agree with the comments above that the most likely explanation is lower flue gas temperatures from a more efficient water heater. You probably need to either reposition the water heater so that the exhaust pathway is shorter, or you need a power vented water heater.
Topic Author
iamblessed
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by iamblessed »

When I place my hands by vent hood I do not feel any heat. So I figured it was venting well. The pipes get to hot to touch. I did not know they smelled for a few hours when installed.
PoorPlumber
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by PoorPlumber »

Would have to be there to put my hands on things to make a reasonable opinion. Not even sure EXACTLY what kind of heater you have now vs. your old one. Except this new one will be FVIR.

Gas fired appliances are supposed to be calculated for design, supply, and exhaust. And changes to design require recalculating. Especially on a common vent.

A simple old test you can do is bring the water heater to temperature with the burner running. Light a match or small piece of paper and blow it out.
Hold the match/paper near the draft hood (opening at the heater vent) and watch the smoke.
Pulling smoke in-Drafting/venting (How well we don't know.)
Not pulling smoke in efficiently-Not drafting/venting properly.

As mentioned earlier, get a CO detector NOW. Doesn't matter if you have never had one. It's an odorless/invisible gas that makes people just sick enough that people don't want to go to the doctor to figure anything out. So they can stay ill long term with it never knowing it could be corrected.

Or worse, it will kill you and your loved ones.

Call a licensed plumber. They're much cheaper than doctors.

Good Luck! Be safe!
bombcar
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by bombcar »

Your water heater may be backdrafting now, depending. See if opening doors or windows makes it work correctly.

https://structuretech.com/how-to-fix-wa ... kdrafting/

https://structuretech.com/water-heater- ... ing-signs/

Meanwhile, install a smoke alarm with CO monitoring in the room the heater is in, that's just good safety practice.
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windaar
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by windaar »

Lack of draft hood and the poor vent slope gets my attention. Have a local plumber look at it. Not something to fool with.
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bradinsky
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by bradinsky »

It’s a poorly designed vent. Just because it worked in the past doesn’t mean it is safe. Please have someone knowledgeable look at it.
rbd789
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by rbd789 »

We bought a house that was 7 years old at the time. The first time we had the water heater replaced, by a licensed plumber, he did the right thing and pulled a permit. The city inspector came and failed the inspection because the original venting was not up to code, being too small in diameter. The plumber went back and updated the venting, and the installation passed. We have had no issues in the 25 years since. My message to the OP is, please get a licensed professional and make sure they pull the proper permit if one is required. Be safe, your family is important!
popoki
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by popoki »

Where I live, replacing a gas water heater requires a plumbing license, city permit and city inspection, and venting must be added or modified to meet current code. Not a DIY project.
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BIGal
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by BIGal »

This is a job for a professional, period.

In addition to venting, the gas piping also needs to be checked.

I worked for a gas utility and can tell you that, unless you are a licensed professional, you have no business installing a gas water heater.

You are risking carbon monoxide poisoning and if there is a natural gas leak, your entire home.
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id0ntkn0wjack
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by id0ntkn0wjack »

Is this a DIY install and, if so, is your life insurance paid up?

Looks like you are already committeed, but imo natural draft gas water heaters should be outlawed and replaced with either a power vented unit or, even better, a heat pump water heater (which qualify for rebates/credits under President Biden's Inflation Reduction Act).

Carbon Monoxide is a silent odorless killer.
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iamblessed
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Re: Installed a new water heater. Now getting some exhaust flumes when the burner is on. Can you help solve this proble

Post by iamblessed »

I placed a Carbon Monoxide detector all around it. It did not go off. It must be the newness of the tank. I will leave the detector plugged in by it.
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