Wye duct with electrical damper for ducting

Does one exist? I’m going to make the switch to CO2 but would like to retain the ability to exhaust at night using the same fan and filter. I was thinking of installing a electronically switchable wye type splitter on a timer so my filter can run as a scrubber during the day and an exhaust at “night” when CO2 isn’t being generated.

I know I can get a regular wye splitter and just toss a damper on one side but was wondering if anyone knew of another way.

If it is doable are there any other should be aware of? Like noise or reduced efficiency.

Here is a pic of my setup. Wye and damper would go just after the silencer pipe.
Another option I have would be to run the spare 4” fan and filter I have exclusively as an exhaust and let the 8” fan and filter just be a scrubber.

Any input is appreciated. Thanks!

I've often thought of and wondered the same thing, never seen it done so ill be here watching for ideas,lol.

I couldn’t find anything. Best bet is a Y splitter with an electric damper on a timer. I’m just gonna run a scrubber with a separate small fan and carbon filter to vent at night.

TBH using a damper on both sides is probably the best option. One normally open and one normally closed. It will get cumbersome but thats the fix. I am not aware of an all in one type solution. Adjusting the spring tension is key with those.

The separate scrubber is by far the best fix. Really doubling up on the odor control. Smart move. With all those chinese moving parts on the 2 zone damper contraption it's just a matter of time before a gremlin pops up.

Renfro said:

TBH using a damper on both sides is probably the best option. One normally open and one normally closed. It will get cumbersome but thats the fix. I am not aware of an all in one type solution. Adjusting the spring tension is key with those.

The separate scrubber is by far the best fix. Really doubling up on the odor control. Smart move. With all those chinese moving parts on the 2 zone damper contraption it's just a matter of time before a gremlin pops up.

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that’s what i was afraid of. Those motorized dampers all looked cheap and I don’t wanna manually adjust. Thanks

I really think it's a product a lot of people would buy if someone came out with a sturdy one. A lot of sealed rooms vent at lights off to dump the excess c02 and any ethylene gas that has built up from a burner. Having to have a carbon filter that is only used a couple times a day seems like a waste for sure when it could be scrubbing the rest of the day. I smoke and get all kinda ideas. The best would be a mini split that is capable of running 2 large heads from an outside unit on a flip for people who run two rooms opposite each other. If I was an HVAC tech I'd try to figure it out seems like you could just use a branch box and put the head units on timers. But I'm sure it could be a little more involved might need a special branch box that would shut off flow to one unit and divert it to the other. Anyways if you wanna guinea pig the electronic damper idea I'll watch and see how it works cause I could benefit from the same but don't have money to experiment with atm.

Apalchen said:

I really think it's a product a lot of people would buy if someone came out with a sturdy one. A lot of sealed rooms vent at lights off to dump the excess c02 and any ethylene gas that has built up from a burner. Having to have a carbon filter that is only used a couple times a day seems like a waste for sure when it could be scrubbing the rest of the day. I smoke and get all kinda ideas. The best would be a mini split that is capable of running 2 large heads from an outside unit on a flip for people who run two rooms opposite each other. If I was an HVAC tech I'd try to figure it out seems like you could just use a branch box and put the head units on timers. But I'm sure it could be a little more involved might need a special branch box that would shut off flow to one unit and divert it to the other. Anyways if you wanna guinea pig the electronic damper idea I'll watch and see how it works cause I could benefit from the same but don't have money to experiment with atm.

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I’m just gonna go with a small 4” fan and filter combo cause I already have it. It’s too small for the space in its own but since the 8” fan and filter are already scrubbing the filter won’t get overwhelmed.

I’m hoping that the scrubber works well enough to run my single hose AC without a filter on it as well. I know it’ll suck some CO2 out but I don’t think I’ll need to run it often. I bought a CO2 generator that’s oversized for my space so in theory it should be able to keep up and natural gas is dirt cheap anyway.

@Renfro you seem to be the go to guy for room design. Do you think it’ll work?

I have serious doubts about the single hose ac. And also how much c02 will be exhausted. My total rooms size is like 250 sq ft with 10 ft ceilings. And the single hose ac caused enough negative pressure to suck in the tent door I used to seal the doorway to my room. It also put out quite a bit of smell into my yard, for me wasn't a huge deal it's legal here and my neighbors aren't close but it still wasn't ideal. My portable can work as either single or dual hose, but rather not cut more holes since I got a mini split being delivered tomorrow.

Apalchen said:

I have serious doubts about the single hose ac. And also how much c02 will be exhausted. My total rooms size is like 250 sq ft with 10 ft ceilings. And the single hose ac caused enough negative pressure to suck in the tent door I used to seal the doorway to my room. It also put out quite a bit of smell into my yard, for me wasn't a huge deal it's legal here and my neighbors aren't close but it still wasn't ideal. My portable can work as either single or dual hose, but rather not cut more holes since I got a mini split being delivered tomorrow.

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It’s legal here too but it more of a courtesy to the neighbors and to keep the dickheads away.

My structure is already cut for a dual hose so it’s not a big deal if I have to get one. I gotta wait and see how much the burner raises room temps and see how the plants respond before I pick an AC

Apalchen said:

I have serious doubts about the single hose ac. And also how much c02 will be exhausted. My total rooms size is like 250 sq ft with 10 ft ceilings. And the single hose ac caused enough negative pressure to suck in the tent door I used to seal the doorway to my room. It also put out quite a bit of smell into my yard, for me wasn't a huge deal it's legal here and my neighbors aren't close but it still wasn't ideal. My portable can work as either single or dual hose, but rather not cut more holes since I got a mini split being delivered tomorrow.

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Let me know how it goes with your minisplit. After being adamant about trying to make it work without one over the last few days I finally relented and ordered one. Should be here in two weeks. Are you installing it yourself? The one I ordered has pre-charged lines so I don’t need an HVAC tech. A buddy of mine is an electrician so he’s gonna come do the wiring and I’ll do everything else. I’m a former motorcycle and auto tech so I consider myself fairly handy.

sf_frankie said:

Let me know how it goes with your minisplit. After being adamant about trying to make it work without one over the last few days I finally relented and ordered one. Should be here in two weeks. Are you installing it yourself? The one I ordered has pre-charged lines so I don’t need an HVAC tech. A buddy of mine is an electrician so he’s gonna come do the wiring and I’ll do everything else. I’m a former motorcycle and auto tech so I consider myself fairly handy.

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I am doing it myself should be here today hopefully. I really don't consider myself that handy, but I did build out the whole building wiring and all. I ordered the Mr cool 36k btu which also has the diy linesets. I know it's not a Mitsubishi but the quotes I was getting from installers to do my whole building was 18k area. I just don't have that so I bought one of these to try and if all else goes well I'll order a couple more for the other rooms. You will be happy with the mini split vs other ac, I had one at my last spot and being able to control temp with precision is def worth it and will pay for itself.

sf_frankie said:

Let me know how it goes with your minisplit. After being adamant about trying to make it work without one over the last few days I finally relented and ordered one. Should be here in two weeks. Are you installing it yourself? The one I ordered has pre-charged lines so I don’t need an HVAC tech. A buddy of mine is an electrician so he’s gonna come do the wiring and I’ll do everything else. I’m a former motorcycle and auto tech so I consider myself fairly handy.

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There is no way the lines are pre charged
You will have to run the line sets, flare and cut them, nitrogen test then vacuum them. Using manifold gauges you then close the vacuum side and open up the “precharge” which is in the condensing unit (2 valves)

furthermore there are maximum and minimum line set distances. You will have to add refrigerant per foot beyond The precharged Length.
I know it seems like it might be easy to do if you’re mechanically inclined, but you will toast that system if it isn’t installed correctly and you also lose a lot of efficiency and lifetime

To the op; I like the 4” fan idea, it seems cheap and simplistic

If either of you have any questions about trying to install these I can help, let me know.

all of the instructions are in the installation manual, and you can do it. It will take some equipment though that most people don’t have

Nizza said:

There is no way the lines are pre charged
You will have to run the line sets, flare and cut them, nitrogen test then vacuum them. Using manifold gauges you then close the vacuum side and open up the “precharge” which is in the condensing unit (2 valves)

furthermore there are maximum and minimum line set distances. You will have to add refrigerant per foot beyond The precharged Length.
I know it seems like it might be easy to do if you’re mechanically inclined, but you will toast that system if it isn’t installed correctly and you also lose a lot of efficiency and lifetime

To the op; I like the 4” fan idea, it seems cheap and simplistic

Click to expand...

There are mini splits that come with pre vacced lines now. They have fittings on each end of the line set that don't open until torqued down. They are made to be diy units, they do cost a little more but you don't need an HVAC tech to install. I'm installing one today hopefully as long as it arrives. I've had terrible luck with HVAC guys in the past so I decided to do it myself but didn't have all the tools needed so went this route.

Edit: I have nothing against ac guys just haven't had good luck and my quotes were just way more than I can afford right now. And I don't have access to nitrogen tanks, or familiar with how to use them.

Apalchen said:

There are mini splits that come with pre vacced lines now. They have fittings on each end of the line set that don't open until torqued down. They are made to be diy units, they do cost a little more but you don't need an HVAC tech to install. I'm installing one today hopefully as long as it arrives. I've had terrible luck with HVAC guys in the past so I decided to do it myself but didn't have all the tools needed so went this route.

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That’s pretty cool shit I didn’t know there were products like that
It would help a lot of growers if you logged a journal about the steps of installing this. It would definitely save people money from having to pay a tech

I called the freight company and they said it didn't get loaded on truck today and rescheduled for tomorrow. So I'll update you guys then with how it goes.

Nizza said:

If either of you have any questions about trying to install these I can help, let me know.

all of the instructions are in the installation manual, and you can do it. It will take some equipment though that most people don’t have

Click to expand...

I downloaded the instruction manual and then watched a YouTube video and it all looked pretty straightforward. The ad didn’t specify needing special tools but in the YouTube video the guy used a manifold gauge to vac the lines. Luckily I have access to a manifold gauge and a compressor so I’ll grab it just in case. I wonder if automotive AC certs apply to home setups? AC cert classes are really all about refrigerant handling anyway. I’ll have to look into it and see as half the people I know are AC certified for cars, if not I’ll get an HVAC guy out to vac the lines. If you get caught messing with that shit on a car without a cert the fine is like $30k! Plus it’s

Nizza said:

There is no way the lines are pre charged
You will have to run the line sets, flare and cut them, nitrogen test then vacuum them. Using manifold gauges you then close the vacuum side and open up the “precharge” which is in the condensing unit (2 valves)

furthermore there are maximum and minimum line set distances. You will have to add refrigerant per foot beyond The precharged Length.
I know it seems like it might be easy to do if you’re mechanically inclined, but you will toast that system if it isn’t installed correctly and you also lose a lot of efficiency and lifetime

To the op; I like the 4” fan idea, it seems cheap and simplistic

Click to expand...

I should have wrote pre-vacced instead of pre-charged. My unit comes with 16’ hoses so I’ll have some extra length sitting outside by the unit. Not a huge deal. Don’t need to flare or cut them.

Nizza said:

If either of you have any questions about trying to install these I can help, let me know.

all of the instructions are in the installation manual, and you can do it. It will take some equipment though that most people don’t have

Click to expand...

I downloaded the instruction manual and then watched a YouTube video and it all looked pretty straightforward. The ad didn’t specify needing special tools but in the YouTube video the guy used a manifold gauge and compressor to add vacuum to the lines to check for leaks instead of pressurizing with nitrogen. Luckily I have access to a manifold gauge and a compressor so I’ll grab it just in case. I wonder if automotive AC certs apply to home setups? AC cert classes are really all about refrigerant handling anyway, just a different type. I’ll have to look into it and see as half the people I know are AC certified for cars, if not I’ll get an HVAC guy out to leak test and then charge the lines. If you get caught messing with that shit on a car without a cert the fine is like $30k! I want no part of that plus it’s the responsible thing to do. I’ve tried to make sure not to cut corners on any part of this build.

sf_frankie said:

I downloaded the instruction manual and then watched a YouTube video and it all looked pretty straightforward. The ad didn’t specify needing special tools but in the YouTube video the guy used a manifold gauge to vac the lines. Luckily I have access to a manifold gauge and a compressor so I’ll grab it just in case. I wonder if automotive AC certs apply to home setups? AC cert classes are really all about refrigerant handling anyway. I’ll have to look into it and see as half the people I know are AC certified for cars, if not I’ll get an HVAC guy out to vac the lines. If you get caught messing with that shit on a car without a cert the fine is like $30k! Plus it’s


I should have wrote pre-vacced instead of pre-charged. My unit comes with 16’ hoses so I’ll have some extra length sitting outside by the unit. Not a huge deal. Don’t need to flare or cut them.




I downloaded the instruction manual and then watched a YouTube video and it all looked pretty straightforward. The ad didn’t specify needing special tools but in the YouTube video the guy used a manifold gauge and compressor to add vacuum to the lines to check for leaks instead of pressurizing with nitrogen. Luckily I have access to a manifold gauge and a compressor so I’ll grab it just in case. I wonder if automotive AC certs apply to home setups? AC cert classes are really all about refrigerant handling anyway, just a different type. I’ll have to look into it and see as half the people I know are AC certified for cars, if not I’ll get an HVAC guy out to leak test and then charge the lines. If you get caught messing with that shit on a car without a cert the fine is like $30k! I want no part of that plus it’s the responsible thing to do. I’ve tried to make sure not to cut corners on any part of this build.

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The brand I went with was Mr. Cool. They make a diy one that doesn't require any of the vaccuming. Same brand makes cheaper ones that you do have to do all that on but I'd just have ordered a Daikin again if I was gonna do all that.

Aura makes a diy version as well, and I've seen a few others on the big box stores websites that I can't remember the brand of.

Apalchen said:

The brand I went with was Mr. Cool. They make a diy one that doesn't require any of the vaccuming. Same brand makes cheaper ones that you do have to do all that on but I'd just have ordered a Daikin again if I was gonna do all that.

Aura makes a diy version as well, and I've seen a few others on the big box stores websites that I can't remember the brand of.

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I got a cheap Pioneer unit from amazon. More than likely some cheap Chinese crap. It had awesome reviews both on and off amazon though. Probably won’t last as long as a Mitsubishi or Daikin but I really only expect to use it for two years. It was only like $800 with tax, so stupid cheap. Can’t expect much. It’s got more than enough BTU for my small room so it won’t be stressed from running nonstop.

Nizza said:

That’s pretty cool shit I didn’t know there were products like that
It would help a lot of growers if you logged a journal about the steps of installing this. It would definitely save people money from having to pay a tech

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I’ll try and journal the install. This guy made a video of him installing the exact same unit that I found helpful. Honestly, the hardest part for me will be finding a stud in the wall. For some reason, stud finders have been lying to me my entire life lol. My poor wall suffers. I’ve drilled one to many exploratory holes in this build cause I don’t trust the stud finder.