I hope this info saves someone or their crop.

[smurfin'herb]

Its not every day that i learn something new, but i met a fine gentleman today that is an overly experienced hvac tech. He taught me some solid info, so i will share it with you. Ive learned so much here, this is the least i can do.

#1... If you vent into your chimney.....
Air pressure in a chimney is always negative pressure. If you vent into it, you are creating positive pressure. This creates an "air curtain" over your hot water vent and your furnace vent which are both tapped into the chimney of your house at the basement or first floor level. What happens now is, the positive pressure you are applying now restricts/blocks the flow of the carbon monoxide from your heater and hot water heater, and can force it to backflow into the room!!!!!! There is a fix to this, but i dont understand it well enough yet to say. I think it has to do with dropping a pipe down your chimney and hooking it up to the vents that are being restricted. I will update this one when i have a better understanding.

#2... For all people who use a/c or dehumidifer water for their plants...
Make sure that the coil in your appliance is NOT COPPER!! The condensation contains traces of copper and can/will poison your plants.

#3.... AC UNITS... He said the only a/c units that dont leak out smell or c02 are the mini splits. Everything else does, at least according to him. I even specifically asked if the portable dual hose units did this, and he said yes.

#4... 6" flex duct is only capable of moving about 90cfm.... That just sounds like a minute amount of movement tho...

#5...He had a simple formula for figuring out how many btu's lights put out!! Heres the numbers, but i just rounded them since they were so close.
1000watt open= 3000btu
1000watt air cooled= 2000btu
600watt open= 2000btu
600watt air cooled=1200btu

Those are just the rough numbers from what i remember, but i will update them once i ask him again, those are close tho. Also, the air cooled numbers are only if the lights are setup and cooled in an efficient way.

#6.. Its always best to run the next size up ducting as to what your fan accepts. I.E. If you have a 8in. fan, use 10 in. duct in order to get the max cfm's out of your fan.

#7 Rigid duct can move almost twice as much air as flex. It makes no sense to have 6" in flex duct installed and then use rigid duct further down the line.

I just met this guy today, but he is cool and he REALLY knows his shit. He actually teaches duct design and installation classes. I was rather stoned when i learned all this info, so some of this may be a tad squewed but i will fix it once i get the solid idea of some of this stuff. thx for listening.

 

[NorthernKronic]

The only one I question is #3..

It is my understanding and most others here on IC that windowbanger AC's are the only kind that dont leak any smell. Can anyone else back me up on this because Im almost positive this is the truth?

-N.Kron

 

[dongle69]

I know that the fine gentleman is full of shit about #4.
As for #2, the amount of copper is pretty minute, especially given that the plants are only cycled for a few months.
And yes to the above poster mentioning #3, many window units don't leak when used in the correct mode.
I could keep going but I'm sure others will contribute...

 

[WeeD22MaN]

We vent our portable exhaust threw a 6" carbon. We attached a 6" vortex to it and to the 4" blower leaving a gap for excess air to be pulled threw. Kinda expensive and a decent amount of work but seems to do the job Pictures attached.

Stay safe.

WeedMan

 

[asher1er]

i use standard central ac units n dont have any leaks of smell he was prolly talkin in the portable scene when it comes to ac tho.

i agree with dongle, the traces of cooper if any are small.. having 2 5ton units, a santa fe dehu and 2 lg 65pint dehu's all producing water on a daily basis i been using that water for some time now with no ill effects..

i know folks who only use ac and dehu water in there small soil grows with no issues. On a side note, all our water lines which include drinking water are cooper atleast in these parts of the woods

 

[MarquisBlack]

i know folks who only use ac and dehu water in there small soil grows with no issues. On a side note, all our water lines which include drinking water are cooper atleast in these parts of the woods

Not saying that I agree that Dehuey water is bad for you, I really have no idea. But as far as drinking pipes being copper, the major difference here would be that with an A/C and (I believe) a Dehuey, you're using what's called the "Phase Transition" or "Phase Change" effect, in which the all of the moisture is transferred from "Side to side" through the copper itself. This could cause contamination that might not otherwise occur. Think colloidal silver, though I'm not sure if this would ionize the copper, but you get what I'm saying.

 

[smurfin'herb]

I know that the fine gentleman is full of shit about #4.
As for #2, the amount of copper is pretty minute, especially given that the plants are only cycled for a few months.
And yes to the above poster mentioning #3, many window units don't leak when used in the correct mode.
I could keep going but I'm sure others will contribute...

Hello dongle, your right, #4 does sound a bit off, but like i said, you have to take this info with a grain of salt for now until i get the full recap of what he was saying. I was high and caught offguard when i met him, so it made it difficult to sink in. Plus, i had to of asked him like 30 questions so its hard to remember every detail of every answer he gave me.

Next time i will ask him specifically his reason as to why window units leak smell etc...

Please people, dont bash me too hard, im just trying to help here. Once i get the info all straightened out this will be legit. I mainly just wanted to let everyone be aware of the risk you take when you vent out a chimney.

WEEDMAN, good idea man. How did you match up the cfm's of the exhaust from the a/c, to those of the fan, and then the carbon filter restriction...? Seems complicated. Unless you just hooked it all up and got lucky and it works good. Either way, good job.

 

[Hydro-Soil]

The only one I question is #3..

It is my understanding and most others here on IC that windowbanger AC's are the only kind that dont leak any smell. Can anyone else back me up on this because Im almost positive this is the truth?

I don't know what a windowbanger is but if you're talking a window mounted A/C unit, I know mine certainly leaks odor. It's also a light leak as well. (Need to take it apart and paint the foam inside with a light-proof paint someday)

 

[DrunkenMessiah]

On chimney venting:

This is retarded. There are a million different reasons not to do this, carbon-monoxide blow-back into the house is just one of them. It is completely counter-intuitive, why on earth would anyone do that when the alternative is just as easy (if not easier) and much more effective. You can vent and recirculate through a carbon filter, but you still have to deal with humidity, compounding heat, the borg and many other issues. My favorite ventilation solution comes from JonJaffer, waayy back in the day on the overgrow forums:

How can I vent through the sewer?
Contributed by: JonJaffer

A common alternative to venting up the chimney is venting into the sewer pipe. Depending on how your house is built, if you push air into your sewer pipe, the air may travel up through your house sewer standpipe. However, it is possible to vent directly into the actual sewer system.

Venting into the sewer is generally safe. If someone is working in the sewer nearby, they might smell the sweet pungent aroma of your crop (Not likely at night), but they have no way to tell where on the block it is coming from. Since the pipes large enough to walk in are quite far away from individual homes, the smell has lots of time to dilute.

[Editor's note: the stinky sewer will also hide your crop's odor up to a point. The sewer system itself is sealed, but you should check nearby manholes covers just incase for excessive blower noise and smell. The undeground sewer system will also remove and cool exhaust heat - excellent protection against infrared detection.]


To start you will need to locate your sewer pipe in your basement. This is the pipe coming from your toilet(s) on upper floors.

Near the basement floor, there should be a "Y" connection at an angle, with a cap on it. Some houses have metal pipes, other houses will have ABS or PVC plastic sewer pipes.



You will need a pipe wrench to remove the cap. Sometimes, if the house is very old, you will need to demolish the cap to get it off. You can buy a new one later at the hardware store if you need to.
This will reveal a hole 3 or 4 inches in diameter, depending on where you live, it may even be another size.

CAUTION: Fumes from the sewer can be poisonous, so make sure to use caution when removing the cap, and once a fan is installed, make sure to keep it ON all the time , so that there is no backflow into the home.

You will need to visit a hardware store, and pickup the various connectors and aluminum flex ducting to connect a fan to the hole. The most efficient fans for this purpose are centrifugal inline fans, but a squirrel cage fan will work too. The major difference is power consumption - an inline fan will use about 1/4 the electricity of the same size squirrel cage, they are VERY efficient, but a little bit noisier.

The fan pictured here is 438 cfm, and only uses 115 watts. The inlet and outlet ports are 6 inches in diameter. I use a reducer from 6" to 4", and then I use 4" aluminum dryer ducting to the sewer hole, and of course plenty o' duct tape!

Once you are finished, you can test your work by standing outside the basement door, and holding a lighter to the crack at the bottom of the closed door. The flame should shoot inwards, because air is being drawn from the upstairs.

If you have successfully create this 'negative pressure' environment, there is no way that odorous grow room air can enter the house, hence the smell is contained!

[Editor's note: the sewer contains methane - a smelly and potentially explosive gas! Keep those gases away from your water heater pilot light!

*END CLIP*

I have used this technique to tremendous effect, and you dont even have to do it the way that good old jaffer described. Also, I think it is a lot safer than he describes. He says that someone working in the sewers might smell your crop. I'm sorry, but I don't care how danky your ganja is, there is no fuckin way its going to overpower liquid sewage. Also, in the unfortunate situation that you have to be in a sewer, I don't think that you will be going around inhaling deeply through your nose.

Anyway, I have ventilated countless closet and micro grows into the sewer without having to access the main. Simply find the nearest bathroom or other drain pipe source, cut out 4-6 inches of pipe, plumb in a Y fitting with pipe clamps, set up a medium sized fan in your grow chamber. Cut into the crawl space and plumb the fan to the Y fitting using 4 inch semi-flexible aluminum dryer hose. (has a much better drag coefficient than the fully flexible plastic stuff) Job done. Never worry about smell, heat, humidity or any other ventilation issues ever again. The only issue is if you have a power out, pressurized sewer gas will come into the house right quick. I have solved this issue in all of my installations by using a simple spring-loaded butterfly valve. They are sold at Menards as an energy-saving duct upgrade and similar devices are not hard to come by. As long as the fan runs, it sucks the valve open and little to no flow is lost, but the moment that you cut power the valve snaps shut and makes a relatively good seal.

I know that the fine gentleman is full of shit about #4.

That is an awfully small number that he quotes, it doesn't sound right to me either, but he has a very valid point. Flexible (slinky-style) ducting hose has an absolutely atrocious drag coefficient. Even if you stretch it out perfectly, those little ribs generate massive quantities of turbulence. Imagine millions of tiny vortexes forming on each rib in the duct, creating tiny low-pressure areas that impede the progress of the air mass significantly. I always do my best to use smooth ducting, it takes a massive load off of the fan and lets you get away with using a lower CFM (quieter) fan and narrower pipes. Of course, you can overcome restrictive ducting by just hooking it up to a badass axial fan, but if you are willing to give it a bit of thought some simple smooth tube can save you a lot of money on ventilation. Good luck, and happy gardening!

-DM

 

[Euphrates]

New and Confused.

New and Confused.

#3.... AC UNITS... He said the only a/c units that dont leak out smell or c02 are the mini splits. Everything else does, at least according to him. I even specifically asked if the portable dual hose units did this, and he said yes.

That kind of sucks if that’s true, It seems though the general consensus is, that if used properly, these "window-banger" units won't leak if used in the correct mode.

Questions:
1. What about the portable units as Lowe’s or homedepo that go for around 100, I know this guy said they'd leak, but if used in the correct mode, would they be safe to use on the plants in the room, or stand a chance of having any leaks ?

Portable air conditioners seem kind of pricey online, but I know I’ve seem them cheaper for like around 100 or so in the store. Though it almost seems cheaper to buy 2 vortex fans, if heat is not a severe issue. The A/C mini splits seem even more pricey, one could get all he needs for a good setup for the amounts I've found on those units.

2. I assume just because it’s a window “banger” doesn’t mean it has to go in window, right? Might be a dumb question but I really don’t know.

3. In general, what is the correct mode on a A/C ? I assume not to high of a setting would be correct, but again I really don‘t know.

3. Are we talking about a Freon leak ? I hope not.

If anyone can answer any of these questions, it would be well appreciated.

Weed22Man: I assume that’s a A/C in your room ?


Thank-You

 

[smurfin'herb]

On chimney venting:

This is retarded. There are a million different reasons not to do this, carbon-monoxide blow-back into the house is just one of them. It is completely counter-intuitive, why on earth would anyone do that when the alternative is just as easy (if not easier) and much more effective. You can vent and recirculate through a carbon filter, but you still have to deal with humidity, compounding heat, the borg and many other issues. My favorite ventilation solution comes from JonJaffer, waayy back in the day on the overgrow forums:

How can I vent through the sewer?
Contributed by: JonJaffer

A common alternative to venting up the chimney is venting into the sewer pipe. Depending on how your house is built, if you push air into your sewer pipe, the air may travel up through your house sewer standpipe. However, it is possible to vent directly into the actual sewer system.

Venting into the sewer is generally safe. If someone is working in the sewer nearby, they might smell the sweet pungent aroma of your crop (Not likely at night), but they have no way to tell where on the block it is coming from. Since the pipes large enough to walk in are quite far away from individual homes, the smell has lots of time to dilute.

[Editor's note: the stinky sewer will also hide your crop's odor up to a point. The sewer system itself is sealed, but you should check nearby manholes covers just incase for excessive blower noise and smell. The undeground sewer system will also remove and cool exhaust heat - excellent protection against infrared detection.]


To start you will need to locate your sewer pipe in your basement. This is the pipe coming from your toilet(s) on upper floors.

Near the basement floor, there should be a "Y" connection at an angle, with a cap on it. Some houses have metal pipes, other houses will have ABS or PVC plastic sewer pipes.



You will need a pipe wrench to remove the cap. Sometimes, if the house is very old, you will need to demolish the cap to get it off. You can buy a new one later at the hardware store if you need to.
This will reveal a hole 3 or 4 inches in diameter, depending on where you live, it may even be another size.

CAUTION: Fumes from the sewer can be poisonous, so make sure to use caution when removing the cap, and once a fan is installed, make sure to keep it ON all the time , so that there is no backflow into the home.

You will need to visit a hardware store, and pickup the various connectors and aluminum flex ducting to connect a fan to the hole. The most efficient fans for this purpose are centrifugal inline fans, but a squirrel cage fan will work too. The major difference is power consumption - an inline fan will use about 1/4 the electricity of the same size squirrel cage, they are VERY efficient, but a little bit noisier.

The fan pictured here is 438 cfm, and only uses 115 watts. The inlet and outlet ports are 6 inches in diameter. I use a reducer from 6" to 4", and then I use 4" aluminum dryer ducting to the sewer hole, and of course plenty o' duct tape!

Once you are finished, you can test your work by standing outside the basement door, and holding a lighter to the crack at the bottom of the closed door. The flame should shoot inwards, because air is being drawn from the upstairs.

If you have successfully create this 'negative pressure' environment, there is no way that odorous grow room air can enter the house, hence the smell is contained!

[Editor's note: the sewer contains methane - a smelly and potentially explosive gas! Keep those gases away from your water heater pilot light!

*END CLIP*

I have used this technique to tremendous effect, and you dont even have to do it the way that good old jaffer described. Also, I think it is a lot safer than he describes. He says that someone working in the sewers might smell your crop. I'm sorry, but I don't care how danky your ganja is, there is no fuckin way its going to overpower liquid sewage. Also, in the unfortunate situation that you have to be in a sewer, I don't think that you will be going around inhaling deeply through your nose.

Anyway, I have ventilated countless closet and micro grows into the sewer without having to access the main. Simply find the nearest bathroom or other drain pipe source, cut out 4-6 inches of pipe, plumb in a Y fitting with pipe clamps, set up a medium sized fan in your grow chamber. Cut into the crawl space and plumb the fan to the Y fitting using 4 inch semi-flexible aluminum dryer hose. (has a much better drag coefficient than the fully flexible plastic stuff) Job done. Never worry about smell, heat, humidity or any other ventilation issues ever again. The only issue is if you have a power out, pressurized sewer gas will come into the house right quick. I have solved this issue in all of my installations by using a simple spring-loaded butterfly valve. They are sold at Menards as an energy-saving duct upgrade and similar devices are not hard to come by. As long as the fan runs, it sucks the valve open and little to no flow is lost, but the moment that you cut power the valve snaps shut and makes a relatively good seal.




That is an awfully small number that he quotes, it doesn't sound right to me either, but he has a very valid point. Flexible (slinky-style) ducting hose has an absolutely atrocious drag coefficient. Even if you stretch it out perfectly, those little ribs generate massive quantities of turbulence. Imagine millions of tiny vortexes forming on each rib in the duct, creating tiny low-pressure areas that impede the progress of the air mass significantly. I always do my best to use smooth ducting, it takes a massive load off of the fan and lets you get away with using a lower CFM (quieter) fan and narrower pipes. Of course, you can overcome restrictive ducting by just hooking it up to a badass axial fan, but if you are willing to give it a bit of thought some simple smooth tube can save you a lot of money on ventilation. Good luck, and happy gardening!

-DM

Good post man. I like the butterfly backup idea. The idea of venting into my sewer has always scared me tho. What if the sewer backs up from a hard rain or somethin? Also, wont there be backsplash from shit that goes down the pipe? I know its a Y piece, but i would figure you would still get some fecal residue up in there. Have you ever seen this happen?

 

[DrunkenMessiah]

Good post man. I like the butterfly backup idea. The idea of venting into my sewer has always scared me tho. What if the sewer backs up from a hard rain or somethin? Also, wont there be backsplash from shit that goes down the pipe? I know its a Y piece, but i would figure you would still get some fecal residue up in there. Have you ever seen this happen?

If the sewer backs up that much you have far bigger problems than sewage dribbling into your vent duct, such as the fact that your house would be at least partially under water in such a situation. Sewers are meant to keep the stuff in them from getting out, but when flooding happens there is nothing to be done about the water table invading the sewer space. Trust me, with the way that sewer systems work it is impossible for there to be a pressurized back-up like you described. The only way something like that can happen is if the water table rises sufficiently high, and as I said if this happens ur fucked anyway.

As for splashing from normal sewer use: you have to be careful with your geometry and use a little common sense. All drain lines, no matter how small, have to run in a downhill direction. Simply place the opening of the Y-pipe 180 degrees from where the water wants to rest and facing in the uphill direction. (its a Y, not a T, this is important) This makes any form of backsplash impossible. I have done a half-dozen sewer-ventilated grows, they have all worked without a hitch. Only one of those installations was a large fan hooked up to the 4 inch sewer main in the basement like Jon describes. All of the others where much smaller fans ducted into 2 and 3 inch PVC drains coming from sinks, showers and washing machines. All of these drains simply carry grey water, which lacks the frightening lumpyness featured in the full-blown sewer main (which services the toilets). Reguardless though, each of the installations have lead trouble-free lives so far: two of them are going on their fourth year of consecutive use! If the opportunity was there, I would favor sewer venting for any grow appliacation up to around 500 CFM. I think it is the best solution for anything less than full-blown commercial grows. Good luck and happy gardening!

-DM

 

[hoosierdaddy]

Some window ac units have a fresh air vent that allows some air into the recirculating cold air. If the unit has a vent, it can leak air as well as light, and may have to be addressed.
But, not all window units have fresh air vents. And the ones that don't typically won't lose air or light.

While on window ac units...always try to pick one that is manually controlled, as a digital control unit can ruin a grow if the power happens to go off for a second. Lights will come back on, but the ac won't if it's digital. (good luck finding a nice sized manual control these days)

On the flex duct only being able to handle 90 cfm....bullshit. Ask him what power fan are we using to test his theory with? He may just back off his statement right then and there.

 

[Hydro-Soil]

While on window ac units...always try to pick one that is manually controlled, as a digital control unit can ruin a grow if the power happens to go off for a second. Lights will come back on, but the ac won't if it's digital. (good luck finding a nice sized manual control these days).

Would a UPS designed for the same size computer wattage keep a digital window A/C unit from 'tripping' during a power problem?

I ask because I have a digital window unit and have experienced this very situation. A battery backup would help immensely but am looking for someone with actual experience to chime in.

Anyone? D

 

[hoosierdaddy]

Absolutely, Hydro. A UPS is the way to go for all of our electrical needs.
Cheap insurance from momentary and longer black outs.

 

[Duckmang]

Lucky me! I've got two Hvac guys on my block. Recently we took the evaparator out of a larger 220V window unit. We fabricated a fan and blower box for the evaporator which we mounted in the peak of the room. Copper tubing was run to the rest of the unit sitting on a shelf outside the room. The 1" hole in the wall that the tubing goes through is sealed with caulk. Zero leaks! The unit cools nicely but recent temps hasn't needed it. Now that I have temp control with the room sealed, Co2 is next. Geez it never ends.

 

[Hydro-Soil]

It is my understanding and most others here on IC that windowbanger AC's are the only kind that dont leak any smell.

The $99 window A/C from Home Depot (Zenith 5K BTU jobbie) definitely DOES leak smell. It has a simple foam wall between the inside and outside. It also leaks a slight amount of light through same said white foam block.

Just a heads up.

Edit: I don't have a scrubber so if you walked past my place right now you'd smell the sweet odor of C-99 in the air. LOL Gotta F'n love that smell

 

[Lazyman]

Would a UPS designed for the same size computer wattage keep a digital window A/C unit from 'tripping' during a power problem?

I ask because I have a digital window unit and have experienced this very situation. A battery backup would help immensely but am looking for someone with actual experience to chime in.

Anyone? D

An appropriately sized UPS would cost at least double what your air conditioner cost, and is not a recommended application. The initial compressor startup would tax all but a huge UPS, and they get into thousands of $ quickly. Go here for a calculator on how much of a UPS you'd need for any given load:

http://www.apc.com/tools/ups_selector/index.cfm

It would be far cheaper to sell your digital and buy a manual AC, I think Haier makes a couple still.