Hot water tank back draft problem

[Photosynthesis]

So I am setting up a new little spot, and ran into a problem. My new place has a gas water heater, and if I run more than one 8" inline fan outside of the basement the water heater backdrafts back into the basement. There are 2 6" ducts coming from outside to bring fresh air into the basement. These were put in by the builder, not me. Even with those the water heater will backdraft. The plastic ring on one side had melted upon a test run I did.

Is there any way to be able to run more fans outside, and not backdraft?

This is my first spot with a natural gas water heater so it never even crossed my mind until I smelled the backdraft coming into the basement.

It really does limit what I can do. I now have twice the equipment that I am able to use because of this issue.

Thanks!

 

[vostok]

Smelled the backdraft ....?
..explain...?
Avoid having an inlet fan and go passive just the extraction fan will work well
possibly vent out into the boiler space with a carbon filter, the warmth of the boiler will keep the filter going well!

 

[Jhhnn]

You need to slightly pressurize the house by putting stronger fans on the intake than the exhaust. Your problem may intensify when you need to run the furnace, depending.

Get a carbon monoxide detector, in any event.

 

[Philosophelon]

I'm also concerned about "smelling" the backdraft. Carbon monoxide is odorless - is there something wrong with the hot water heater in general, like a gas leak or something? Because even if CO is being sucked into your basement, NG shouldn't be, unless your pilot is out or something.

 

[Ph-patrol]

If you don't have a sealed combustion direct vent water heater you are defiantly pulling air out of the draft hood. If you put light paper near the hood you should be able to see the draft. This very dangerous and deadly. Very hard to help with little info.

Please don't run fan until a solution has bin reached.

 

[Jhhnn]

I'm also concerned about "smelling" the backdraft. Carbon monoxide is odorless - is there something wrong with the hot water heater in general, like a gas leak or something? Because even if CO is being sucked into your basement, NG shouldn't be, unless your pilot is out or something.

Backdraft often creates poor combustion & partially burned hydrocarbons detectable to the human nose.

 

[lvtokerr]

my old man my used to ignore me when i told him that he was fucking an idiot for trying to exhaust grow stuff out his hot water exhaust. he used to complain he couldnt sleep because he couldnt breathe in the basement. goomba still has so much negative pressure its sucking heater exhaust into basement like you guys described. That might be how hes getting very close to 2lbs a light in the middle of summer!

 

[Jhhnn]

I've never tried it, but I get the impression that systems having more than a few lights pretty much demand A/C or some very thoughtful engineering and mods to the structure. The heat output is just too much

The vents you describe were installed to provide combustion air to the furnace & hot water heater. modern houses are tight, won't allow it otherwise. That's why newer high end stuff is direct vent- combustion air is brought in thru a separate pipe in the same opening as the vent, creating an air system separate from the living area itself.

 

[Photosynthesis]

I've never tried it, but I get the impression that systems having more than a few lights pretty much demand A/C or some very thoughtful engineering and mods to the structure. The heat output is just too much

The vents you describe were installed to provide combustion air to the furnace & hot water heater. modern houses are tight, won't allow it otherwise. That's why newer high end stuff is direct vent- combustion air is brought in thru a separate pipe in the same opening as the vent, creating an air system separate from the living area itself.

Do you know of any way to fix this other than AC? I don't have enough power for AC. I designed everything based off of venting out the basement windows only. Multiple small rooms so that they would not singly each create much heat, and I could just exhaust out of the windows.

I had originally setup 3- 8" fans, and 1 6" fan exhausted out of the windows. Well when I turned them all on, and ran the hot water all of the heat came in the basement. That is what melted one of the plastic disks on top of the water heater, and also what brought in an "odor."

I only ran it until I could tell the backdraft was happening. I have performed tests since that involved 1 8" fan, and 1 6" fan, and cranked down a bit they can both run without creating a back draft.

It's funny how overlooking something like this can change things so drastically.

 

[blastfrompast]

What about a simple solution like getting a hole-saw...and punching another hole and adding a dryer vent..

Loosen the seal so to speak.

 

[Photosynthesis]

What about a simple solution like getting a hole-saw...and punching another hole and adding a dryer vent..

Loosen the seal so to speak.

I thought about just cracking a window, but that would only be good in the winter.

Damn you modern construction techniques!!!

 

[Ph-patrol]

Vented air simply travels least path of resistance. So if its easer to pull vented air from the WH flue ,that's were it will pull from. You could frame off and seal the area around water heater and add additional venting through your sill for separate grow room.

To check you could light a couple of cigarettes around WH flue hood and see if its pulling air.

Be safe Brother

 

[Jhhnn]

Do you know of any way to fix this other than AC? I don't have enough power for AC. I designed everything based off of venting out the basement windows only. Multiple small rooms so that they would not singly each create much heat, and I could just exhaust out of the windows.

I had originally setup 3- 8" fans, and 1 6" fan exhausted out of the windows. Well when I turned them all on, and ran the hot water all of the heat came in the basement. That is what melted one of the plastic disks on top of the water heater, and also what brought in an "odor."

I only ran it until I could tell the backdraft was happening. I have performed tests since that involved 1 8" fan, and 1 6" fan, and cranked down a bit they can both run without creating a back draft.

It's funny how overlooking something like this can change things so drastically.

If you can seal the area with the water heater, furnace, & vents, You can then figure out how to create separate airflow for the grow by letting air in somewhere else.

You can create a separate airflow system using insulated vent hoods, backdraft preventers & ducting to keep heat out of the grow. Bring it in through a window, run it though the lights, run it right back out the same window opening if you want. That won't affect the water heater at all.

Lots of different ways to approach it.

 

[Jhhnn]

Whatever you figure out, you can't create negative pressure in the area around the gas fired equipment or you'll keep having the same dangerous problem.

Carbon monoxide detectors are extremely reasonable in price, so do yourself a favor- put one upstairs & one downstairs.

 

[Eighths-n-Aces]

There are 2 6" ducts coming from outside to bring fresh air into the basement. These were put in by the builder, not me. Even with those the water heater will backdraft.

you are pulling so much air into the house that everything including the exhaust for the water heater has turned into a passive intake. you could turn one or both of those 6" ducts into an active intake by putting a fan on it. that should make it so your exhaust fans can stop looking for their own supply of fresh intake air.

you might want to try running the furnace while you are trying to get all this dialed in. the amount of air it will pull in and then exhaust while it is running is going to have a big effect on your project. better to get it figured out before it starts getting cold.

maybe you should consider using the lights to heat the house in winter. you will still need to exhaust some air just too keep the humidity down but it won't be near as much. it is dry enough in colorado to work so that that is what i do ........ public service sent me a home energy report that says i use 144% more electricity than my neighbors (no big fucking surprise there) but it also says i use 59% less natural gas.

 

[Ph-patrol]

ok if your going pull air out of the room and dumping out side with a fan that creates a negative pressure in the room. so the room will want to essentially breath through any means including the hood of water heater. So you could simple add the same size fan and port to drive intake air from outside into the room witch should create a neutral pressure and fix your problem.

Hope that made sense

 

[Photosynthesis]

So I was wondering if I could exhaust into my air vents to keep the air in the house, but still remove the heat from the rooms? Would this work?

 

[Jhhnn]

So I was wondering if I could exhaust into my air vents to keep the air in the house, but still remove the heat from the rooms? Would this work?

It'll work, particularly if you can exhaust into the return plenum. Otherwise, the furnace & the fans can end up fighting each other.

 

[Ph-patrol]

I agree with Jhhnn.It would work good if the furnace was calling. I would say to dump that exhaust air out of your house. You may start growing some thing in your return trunk that you don't want.

In your pans , the WH must be resolved because you don't want carbon monoxide in your basement or being pumped into a trunk line to living area.

Hope some of this is helping

 

[Photosynthesis]

In one room there is a return register. The other room is maybe a foot from the main return line. I can tap the one room into the main line. Can I use the return register in the other room, or would it be better to tap into the main return line as well?

Thanks guys for all of the help!

P.s. buying carbon monoxide detectors tomorrow.