Day time temp bounce

[Dosido41616]

Hey everyone,
I’m trying my first indoor grow as follows,
3.5 x 3.5 x 6 tent
4” infinity cloud line inline duct fan with t stat control
315 watt lec light
Honeywell fan
Window a/c flued to tent
1 gal fabric pots
Coco/perlite mix
24 hour lights on veg.

I’ve been having lots of trouble keeping a steady temp in my grow space. When the a/c is on, the temps get to about 72 the lowest and creeps up to about 76. When the compressor for the a/c shuts down and just has the fan blowing the temp gets up to 83.

RH is bouncy as well. The RH skyrockets above 55% - 60% when just the fan on ac is running and the temp goes up. then when ac kicks back on, the RH drops to 40% and temps go back to low 70’s.

I’ve had the inline fan on high so that the tent walls are sucked in and tried to regulate a/c air and vents so that the walls don’t suck in so much but no changes.

My question is, will this continuous temp bounce every hour or so harm the plants? I can’t seem to figure out why temps and RH are out of wack. I’ve been reading and reading post after post and can’t seem to figure this out. Any advice please!! Literally been babysitting grow room for 3 days.
Thanks everyone and happy high times!!

 

[Kingrow1]

Where is the thermometer and rh meter? If its in direct or indirect light its reading light radiation not real air temps.

You control the room the tent is in and not the tent, with air going through it so fast it will be similar to your room temps and rh.

Too much wind is bad, it needs to be barely precievable - air will circulate enough from your extraction

 

[Dosido41616]

Where is the thermometer and rh meter? If its in direct or indirect light its reading light radiation not real air temps.

You control the room the tent is in and not the tent, with air going through it so fast it will be similar to your room temps and rh.

Too much wind is bad, it needs to be barely precievable - air will circulate enough from your extraction

Thanks Kingro. I do in fact have lots of wind in the tent at the moment. I took the ac vent out and are venting out through the top of the tent out side. Only window ac Is blowing in the room and the tent is sucking in the fresh room air from the bottom. I can’t get the temp below 80 without the fan blasting in there.
I have the temp/ Rh sensor under the light level with the plants tops. We’re should I put it?

 

[Kingrow1]

Thanks Kingro. I do in fact have lots of wind in the tent at the moment. I took the ac vent out and are venting out through the top of the tent out side. Only window ac Is blowing in the room and the tent is sucking in the fresh room air from the bottom. I can’t get the temp below 80 without the fan blasting in there.
I have the temp/ Rh sensor under the light level with the plants tops. We’re should I put it?

I teach tent setup and you now see the reason you cant get under 80f because you have your thermometer in the light. Then most try to compensate by upping wind levels which rarely works as wind dosent cool much.

Move thermometer to the most shaded and coolest part of the tent away from all light and wind as best you can and reduce wind so you have some circulation but nothing much at plant level. Your exhaust should be circulating the wind pretty well as it goes.

Now the temps will rise and fall as the room temps rise and fall so control the room to control the tent. Mainly when you find your real air temps they will be close to your room temps and youll probably not need so.much ac and stuff.

Its slightly complex but you will start to get it. Light is hot but its not what were trying to read and passes unhindered through air and warms any surface in the way which in your case os your thermometer. Leaves need this heat and use transpiration natures most efficient cooling system to deal with this so dont need much help from us

 

[ttystikk]

Extract air from the tent right above the lamp because that's where the heat is coming from.

 

[Dosido41616]

You guys rock! Thanks so much for the advice. I’m going to open another vent were the light is and also take a fan out and move the sensor. Were is usually best for a fan placement? Also temps have been stable at 79 - 80 with 45-50% Rh. Is this a good temp or should it be lower? Remember, I’m going 24/7 with the lights in veg for the moment till I can get the environment stabilized. Then I will do the 18/6 schedule.

 

[ttystikk]

Fans pulling air make things cool, fans pushing air make things hot.

 

[Renfro]

Fans pulling air make things cool, fans pushing air make things hot.

Lost me there. Like a central air system in a home pushes and it works rather well. Please explain?

 

[Renfro]

Hey everyone,
I’m trying my first indoor grow as follows,
3.5 x 3.5 x 6 tent
4” infinity cloud line inline duct fan with t stat control
315 watt lec light
Honeywell fan
Window a/c flued to tent
1 gal fabric pots
Coco/perlite mix
24 hour lights on veg.

I’ve been having lots of trouble keeping a steady temp in my grow space. When the a/c is on, the temps get to about 72 the lowest and creeps up to about 76. When the compressor for the a/c shuts down and just has the fan blowing the temp gets up to 83.

RH is bouncy as well. The RH skyrockets above 55% - 60% when just the fan on ac is running and the temp goes up. then when ac kicks back on, the RH drops to 40% and temps go back to low 70’s.

I’ve had the inline fan on high so that the tent walls are sucked in and tried to regulate a/c air and vents so that the walls don’t suck in so much but no changes.

My question is, will this continuous temp bounce every hour or so harm the plants? I can’t seem to figure out why temps and RH are out of wack. I’ve been reading and reading post after post and can’t seem to figure this out. Any advice please!! Literally been babysitting grow room for 3 days.
Thanks everyone and happy high times!!
View attachment 4390863 View attachment 4390864

If the temp is creeping up why does the AC compressor kick off? It shouldn't kick off unless it cools to the setpoint.

 

[Renfro]

It sounds like the AC compressor is overheating for some reason and this is causing it's internal thermal protection to kick the compressor off.

 

[ttystikk]

Lost me there. Like a central air system in a home pushes and it works rather well. Please explain?

Set up a fan to draw air through a vented hood with the lamp running, then turn it around and have it push. You'll see what I'm talking about.

 

[Renfro]

Set up a fan to draw air through a vented hood with the lamp running, then turn it around and have it push. You'll see what I'm talking about.

So air leaks in the hood?

 

[ttystikk]

So air leaks in the hood?

No. Air is a compressible fluid, and when compressed it heats up. Conversely, when pressure drops, so does temperature. Gas law.

 

[Renfro]

Well with an open ended system I don't see there being enough pressure to significantly warm the air. If that is happening then there is a lot of static pressure loss.

 

[ttystikk]

Well with an open ended system I don't see there being enough pressure to significantly warm the air. If that is happening then there is a lot of static pressure loss.

I did this experiment myself with an oversized Magnum hood with 8" vents and an 8" fan. I fired up a standard Plantmax 1000W HPS lamp and let it run for 20 minutes to come up to temperature. There was no ducting installed on either side of the hood, just an 8" axial flow fan, so no restrictions other than the size of the openings themselves.

When I pushed the air through, the hood got almost too hot to touch.

When I turned the fan around so it was drawing air through the hood, it cooled right off until the hood felt cool.

Try it yourself; you'll be as surprised as I was at the difference!

 

[Renfro]

I did this experiment myself with an oversized Magnum hood with 8" vents and an 8" fan. I fired up a standard Plantmax 1000W HPS lamp and let it run for 20 minutes to come up to temperature. There was no ducting installed on either side of the hood, just an 8" axial flow fan, so no restrictions other than the size of the openings themselves.

When I pushed the air through, the hood got almost too hot to touch.

When I turned the fan around so it was drawing air through the hood, it cooled right off until the hood felt cool.

Try it yourself; you'll be as surprised as I was at the difference!

Now that sir was a productive post. Thanks!

 

[Kingrow1]

You guys rock! Thanks so much for the advice. I’m going to open another vent were the light is and also take a fan out and move the sensor. Were is usually best for a fan placement? Also temps have been stable at 79 - 80 with 45-50% Rh. Is this a good temp or should it be lower? Remember, I’m going 24/7 with the lights in veg for the moment till I can get the environment stabilized. Then I will do the 18/6 schedule.

It dosent matter where you place an exhaust as it still exhausts the same volume of air. Fans make circulation but a windy tent is a wind tunnel not a warm plesant sunny day.

Hoping you have moved thermometer to a shaded place and seen a temp drop

 

[Dosido41616]

Kingro!
100%! 77-81 degree temps with RH of 49%-55%. They seem to be loving it!! Owe you one my green brother.

In your opinion, will they do better on an 18/6 schedule or 24 hour?

 

[Kingrow1]

Kingro!
100%! 77-81 degree temps with RH of 49%-55%. They seem to be loving it!! Owe you one my green brother.

In your opinion, will they do better on an 18/6 schedule or 24 hour?

What are the room temps the tent is in?

18/6 is preferable if you have good lights off temps and stuff but growers manage on both so more a personal choice. I like some dark period though so 18/6 does me just fine

 

[ttystikk]

It dosent matter where you place an exhaust as it still exhausts the same volume of air. Fans make circulation but a windy tent is a wind tunnel not a warm plesant sunny day.

Hoping you have moved thermometer to a shaded place and seen a temp drop

Bullshit. Placing the exhaust over heat source gets the heat out. Placing it at the bottom of the tent is useless.