Grow room fan question for temperature control and dark cycle use

Hey everyone,

I've been running a 10 inch outlet fan and filter and an 8 inch intake fan to control odor and temps in my bloom room. They are hooked into a splitter which is plugged into a CAP controller which turns them on when temps get above 75 in the room. Here is my dilemma. During the dark period I want the fans to kick on every so often (maybe once an hour for a few minutes) to clear the stagnant air from the room, reducing smell buildup and relieving moisture heavy air that increases the growth of powdery mildew and mold. The plants naturally breathing and perspiring builds up a lot of 'wet' air while the lights are off for 12 hours.

The problem is, during the winter the room stays very cool during the dark period and the fans will not turn on from the CAP controller. I want to find a way to leave my fans plugged into the temp sensor to operate as normal during daytime, but turn on once an hour for a brief time during the dark period without having to unplug the fans every dark cycle from the temp controller and plug them into a timer. I want the fans to be automated still, but switch to a temperature independent timer during the dark automatically rather than unplugging them myself. Anyone know how I could set up this duality to work? Has anyone figured out a good solution to a similar problem?

With some controllers you can set idle speeds.


If the CAP controller you have has this you could set idle speed to something like 15% that way they would always run at that speed unless temps increased.



J

meybe add a 2nd fan,much smaller on a timer? I have run a PC fan 24/7 on a room to keep some air moving while using a bigger fan on a thermostat to control temps

jondamon said:

With some controllers you can set idle speeds.


If the CAP controller you have has this you could set idle speed to something like 15% that way they would always run at that speed unless temps increased.



J

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I'll Have to browse the catalogs and look for a controller with an idle speed setting, that would probably work pretty well. The CAP controllers I've seen don't have that, so I'll widen my net. Thanks for the idea, had no idea there was such a thing!

mrmadcow said:

meybe add a 2nd fan,much smaller on a timer? I have run a PC fan 24/7 on a room to keep some air moving while using a bigger fan on a thermostat to control temps

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Good idea madcow, I've got an old 8 inch booster fan laying around. I could throw it on a timer and run it every so often in the dark. The only thing that worries me is probably needing to tie into a filter still because venting without a carbon scrubber is gonna stink up the whole block. And if I do that I'm gonna need an electronic dampener on a T or Y vent (so I can close it when the other fan runs, they would have to share the same in and out ducts as my primary fans) and another inline fan (at least a decent fan, cheap ones don't pull through a filter usually in my experience). When you ran your PC fan did you use a filter? Did you have it in a room or a tent?

Yea having a second fan means all kinds of trouble of needing a second filter. I was trying to think of a solution for my own room and finally decided I would just run a dehumidifer in the room at night. unfortunately thats alot of power being used to clear the humidity, and thats also alot of room being used by the dehumidifer considering the small size of my room. But it seems the easiest way to control night time humidity. What is the CAP controller you are talking about Arcadia? my flower room is getting away with no forced venting for now becuase the plants are small and only burning small lights on them, but I need to get this all sorted pretty soon as I'll be putting in more lights for flower

actually having a small fan with a small filter might be the best way to go now that I think of it. Unless there is a device that can run the big fan at a very low idle(if there is something that can do this please show me it, it sounds perfect for what I'm doing). Having a fan run at all times means you always have negative pressure, and any air escaping is being filtered. If you simply turn off all your fans and run a dehumidifier there will no longer be negative pressure and minute air leaks could cause some stink, If you have really smelly plants or lots of plants.

I wish I knew more about electricty... I thought of a cool way to work the fans but I'm not sure if this is safe or if it would work: If you split the power line that runs your fan and had one line go through a timer(or humidistat) and the other line go through a thermostat and then merged the two lines together just before the fan then the fan would run any time either the thermostat or the humidistat were to switch on. But I don't know exactly how you would do that or if it is safe to do.

Heres how I would do that: have an extention cord with 2 plug ins on it. Plug a thermostat into one plugin, and a humidistat into the other. Create a custom extention cord that has 1 female and 2 male ends(this is why its dangerious because if one male becomes unplugged it could electrocute you or short circuit on any conductive material). Plug one of the males into the humidisat and the other male into the thermostat. plug the fan into the female. Mr mad cow you're in the electrician thread alot maybe you can clarify whether or not that will burn down the house lol.

I have a similar setup, fan-wise and controller. Those are large fans, I assume you have a large room? I have done it both ways withs a dehumidifier and a heater. I think the heater is cheaper. I use the radiant heater kind on a timer so it runs only at night with a fan blowing at it away from plants, that's why you need some extra room so it's not near the plants. The heat will help raise dew-point/lower relative humidity as well as make your exhaust come on.

Another alternative is to set your night temp so low that it will never be acheived. Then run your lights through a timer that is on for 12 hours(the daytime) and then flip every other peg for the other 12 hours. During the daylight time your fans will run as normal. During the night your fans will come on for 15 then off for 15 all night long.

Lately though I have just been running the intake and exhaust fans all night.

Good luck grower.

I have to find a solution because my intake temperature is 50 degrees so I cant have that coming in all night long or my plants will not be happy. The heater idea is pretty good, a bit expensive though because to heat my 4x6 room takes 1500watts! Its a cold basement

Thedillestpickle said:

I have to find a solution because my intake temperature is 50 degrees so I cant have that coming in all night long or my plants will not be happy. The heater idea is pretty good, a bit expensive though because to heat my 4x6 room takes 1500watts! Its a cold basement

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I hear you man, winter's a bitch! So is Summer.

On a side note, I use the heat from my lights to heat my house all night long so this helps offset the heating when lights off. Of course this is only possible for certain applications.

I had that same problem..... I dont know how much DIY skills you have or maybe you might know someone but my pops built me a sweet computer proccessor control panal to solve the same type of problem ... Theres is no timers it runs like your computer would on an enternal clock... If the Power were to go out then come back on everything resumes as normal nothing needs to be reset, no timers need to be adjusted for the period power was out.... It has 8 120v outputs connected to 8 different sockets that i can cut power on/off as i wish controlled by the Computer.

This way i just tell the Computer when to turn the fans,lights,ac,heater,dehumidifer and Co2 On/Off and at what times of the cycle to do it.....

Only thing i cant do which is a bummer is change the rpm of the Inline fans im using....Im still using Speed Controllers on all fans i just make sure i plug my speed fan controller into its designated corresponding Socket controlled by the Proccessor....

If you know an electrician or maybe hire one its well worth it if you plan to go long term.... espicailly if your going to go closed loop system in the future

FootClan said:

I had that same problem..... I dont know how much DIY skills you have or maybe you might know someone but my pops built me a sweet computer proccessor control panal to solve the same type of problem ... Theres is no timers it runs like your computer would on an enternal clock... If the Power were to go out then come back on everything resumes as normal nothing needs to be reset, no timers need to be adjusted for the period power was out.... It has 8 120v outputs connected to 8 different sockets that i can cut power on/off as i wish controlled by the Computer.

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that's a beautiful setup, but I'm sure costly. how hard is it to make changes to it? can you adjust the timers easily? what software does it use on the computer?

FootClan said:

I had that same problem..... I dont know how much DIY skills you have or maybe you might know someone but my pops built me a sweet computer proccessor control panal to solve the same type of problem ... Theres is no timers it runs like your computer would on an enternal clock... If the Power were to go out then come back on everything resumes as normal nothing needs to be reset, no timers need to be adjusted for the period power was out.... It has 8 120v outputs connected to 8 different sockets that i can cut power on/off as i wish controlled by the Computer.

This way i just tell the Computer when to turn the fans,lights,ac,heater,dehumidifer and Co2 On/Off and at what times of the cycle to do it.....

Only thing i cant do which is a bummer is change the rpm of the Inline fans im using....Im still using Speed Controllers on all fans i just make sure i plug my speed fan controller into its designated corresponding Socket controlled by the Proccessor....

If you know an electrician or maybe hire one its well worth it if you plan to go long term.... espicailly if your going to go closed loop system in the future

Click to expand...

lol if i had the money I would be trying to get your pops to make me one of those... I wish I knew more about electronics, somone could make alot of money making these for indoor grow use.

What do you use for fan speed control? Ive been looking all over for the right product

I had similar issues with my grow closet. 2000 watt. I added an additional fan, I call it an air exchange fan. All it does is removes air from the closet and pumps it into the main room outside of the closet. This solved a lot of problems for me. Getting moisture out of the closet, balanced out the temps to the house temp, it also made it to where I could reduce the exhaust cfm so I could add additional CO2, it helps circulate the CO2. It probably will not help in your case with the CO2 since yours is a room and not a closet. It should help with your temps and moisture issue, but it will stink up the house.
Just something to consider.

Thedillestpickle said:

lol if i had the money I would be trying to get your pops to make me one of those... I wish I knew more about electronics, somone could make alot of money making these for indoor grow use.

What do you use for fan speed control? Ive been looking all over for the right product

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I use the speedster for fan control. I wanted the wall mount type, but the store was out of them so I had to settle with the speedster. I have no complaints.
With an 8" High out put or larger fan, if you set the control to the lowest setting, it is not enough power for the fan. It needs to be set higher than the minimum.
I would love to have my grow operation hooked up to my computer and have software run everything. I am sure it is possible, because I have an IP security camera that is fully controled with software. Pan, tilt, zoom, motion detection, e-mail capabilities, and so on. They need to make software like that for our growrooms. Then you could monitor and control your growroom from anywhere in the world right from yoru laptop.
Hmmmm, something to look into.

Thedillestpickle said:

lol if i had the money I would be trying to get your pops to make me one of those... I wish I knew more about electronics, somone could make alot of money making these for indoor grow use.

What do you use for fan speed control? Ive been looking all over for the right product

Click to expand...

well if you where in Northern Cali maybe he could make one for you... lol for the right price...... I use a cheap 25 dollar speedy fan controller....

Thedillestpickle said:

Yea having a second fan means all kinds of trouble of needing a second filter. I was trying to think of a solution for my own room and finally decided I would just run a dehumidifer in the room at night. unfortunately thats alot of power being used to clear the humidity, and thats also alot of room being used by the dehumidifer considering the small size of my room. But it seems the easiest way to control night time humidity. What is the CAP controller you are talking about Arcadia? my flower room is getting away with no forced venting for now becuase the plants are small and only burning small lights on them, but I need to get this all sorted pretty soon as I'll be putting in more lights for flower

Click to expand...

Yeah, I've got to bite the bullet with a dehumidifier. Its probably a good idea long term and would be really useful at night. My CAP controller is the day/night temp sensor, I think its a TMP-DNe, I think hydrofarm sells em. I'd have to see a diagram of the way you talked about wiring the fan, but I think you will need a chip/brain/switch of some kind to control the power and relay to the fan. Just splicing in two sources of power would conceivably harm the device unless you have something that regulates when and which source is supplying it.

Thedillestpickle said:

lol if i had the money I would be trying to get your pops to make me one of those... I wish I knew more about electronics, somone could make alot of money making these for indoor grow use.

What do you use for fan speed control? Ive been looking all over for the right product

Click to expand...

he wrote the software....lol well not entirely true he stole a demo software from his work which has the basic program then from there he must write the code for it to talk with the proccessor... So basicly i tell him what i went to happen then he gets on his laptop and programs it to do what i want. the control panel is hardwired to PC inside the house and then he uses his wireless roter to acccess the contol panal from laptop....

Just demo software costs about 16 grand....lol and thats the demo software...Of course he got it for FREE lol....... but he said he can make another one with cheaper more cost effictive software...... Whats cool about this soffware is that its able to show us a bar graph up everything through the day i can not only see current real time temps and Co2 levels and humid. etc etc but i can also see all the temps for the entire day second by second......

CaptainCAVEMAN said:

I have a similar setup, fan-wise and controller. Those are large fans, I assume you have a large room? I have done it both ways withs a dehumidifier and a heater. I think the heater is cheaper. I use the radiant heater kind on a timer so it runs only at night with a fan blowing at it away from plants, that's why you need some extra room so it's not near the plants. The heat will help raise dew-point/lower relative humidity as well as make your exhaust come on.

Another alternative is to set your night temp so low that it will never be acheived. Then run your lights through a timer that is on for 12 hours(the daytime) and then flip every other peg for the other 12 hours. During the daylight time your fans will run as normal. During the night your fans will come on for 15 then off for 15 all night long.

Lately though I have just been running the intake and exhaust fans all night.

Good luck grower.

Click to expand...

That's exactly what I needed man, thank you! Never thought of a heater but its a good thought, and I love the idea of the timer hooked into a day and night temp controller! That's perfect! I could have the fans flip for 15 minutes an hour during the dark and clear the room without buying extra equipment! In fact, I think CAP makes a new day/night temp with a variable speed control built in. I really appreciate the idea, its perfect for my application. Oh and the room is 10x12 with 4000 watts. Plus rep man, great idea!

FootClan said:

I had that same problem..... I dont know how much DIY skills you have or maybe you might know someone but my pops built me a sweet computer proccessor control panal to solve the same type of problem ... Theres is no timers it runs like your computer would on an enternal clock... If the Power were to go out then come back on everything resumes as normal nothing needs to be reset, no timers need to be adjusted for the period power was out.... It has 8 120v outputs connected to 8 different sockets that i can cut power on/off as i wish controlled by the Computer.

This way i just tell the Computer when to turn the fans,lights,ac,heater,dehumidifer and Co2 On/Off and at what times of the cycle to do it.....

Only thing i cant do which is a bummer is change the rpm of the Inline fans im using....Im still using Speed Controllers on all fans i just make sure i plug my speed fan controller into its designated corresponding Socket controlled by the Proccessor....

If you know an electrician or maybe hire one its well worth it if you plan to go long term.... espicailly if your going to go closed loop system in the future

Click to expand...

Wow, what a setup! I've worked construction for awhile and have pretty good DIY skills and a basic knowledge of residential electrical stuff, though that was never my main area of work (did tile mostly). I'd love to see some more pics, maybe a diagram or something if your dad set up some specs when he was brainstorming it. I'm not sure if I could replicate it or come close, but its a great looking rig and I'd love to learn more about it!

heres two displays he designed to help monitor the grow room....I Couldnt find the pics of the bar graphs but im sure you guys know what a bar graph looks like. haha