Mini Split Temp Fluctuations HELP

[Southtex420]

Hello Everyone,

I need help with my sealed room. I am having temperatureand humidity fluctuations and it’s driving me nuts. Temp fluctuates around 10 degrees a couple dozen times per day With lights on. Temp only fluctuates around 4 degrees with lights off. Humidity swings from 40%-75% throughout the day.
Pics below of controller graph.

here’s specs of the room:

12 x 7.5 x 8 foot room
SEALED to the max
Two - Fluence 2p
24k BTU mini split mounted in the center on the 12 foot wall
4 burner c02 generator
110 pint dehumidifier
4’ x 4’ raised beds with living soil
Two oscillating fans
All being controlled with TrolMaster Hydro x

 

[Moe.Red]

That is a lot of swings. I use bottled CO2, I wonder if your CO2 generator is also dumping heat in the room? CO2 + heat go in, the AC takes a minute to catch up, and in the process sucks a lot of humidity out of the room?

Can you make a correlation between the times CO2 is added and your environment swings?

FWIW - using bottles of CO2 I see nothing like this.

I do see when the AC turns on the humidity drops, and although it seems counterintuitive I have to run a humidifier as well as a dehumidifier to even things out.

 

[Southtex420]

Thanks for the suggestion. It is not my c02 burner as it’s only on for 2-4 min per day. The room is extremely sealed. Burner isn’t putting off enough heat for long enough to affect it. I’ve ran it with the c02 burner off to confirm

 

[Southtex420]

My main concern is if it’s as simple as an oversized mini split.

 

[Moe.Red]

I run 2 4x8x8 tents both with 12K mini splits.

12 x 7.5 x 8 = 720
24000/720 = 33.3 BTU per cubic ft.

4 x 8 x 8 = 256
12,000 / 256 = 46.9 BTU per cubic ft.

I'm actually running more power than you without issue.

 

[Moe.Red]

You may need to do some testing with an empty tent once your grow is over. With no plants and good air circulation, no CO2, do the swings still happen when the lights come on? If no, then turn off your fans. Problem? Maybe the air hitting your sensors is not properly mixed and it is chasing itself? Dunno, need to look at one variable at a time to figure it out.

 

[Anthem]

Hello Everyone,

I need help with my sealed room. I am having temperatureand humidity fluctuations and it’s driving me nuts. Temp fluctuates around 10 degrees a couple dozen times per day With lights on. Temp only fluctuates around 4 degrees with lights off. Humidity swings from 40%-75% throughout the day.
Pics below of controller graph.

here’s specs of the room:

12 x 7.5 x 8 foot room
SEALED to the max
Two - Fluence 2p
24k BTU mini split mounted in the center on the 12 foot wall
4 burner c02 generator
110 pint dehumidifier
4’ x 4’ raised beds with living soil
Two oscillating fans
All being controlled with TrolMaster Hydro x

The trolmaster might be the problem. There are a couple of items to take a look at.
#1. Make sure hot start is OFF for the AC. The hot start uses a timer from the time the device last shut off and will not allow the device to go back on until the timer has expired. Meaning that say the ac went off because it had cooled the room to say 80 degrees. It will not come back on for say 15 minutes because of the delay, hence temperature rising in the room.
#2. Take a look at the deadzone inside the systems portion of the program. Set this to just a 2 or 3 degree difference for the ac and you should have better control over your AC.
Please let us know if any of this helps.

 

[srtj]

That seems like a lot of AC for the 2 lights you have. I think the data indicates:

1. AC turns ON at setpoint
2. Room cools room quickly to low end of deadband
3. AC turns OFF
4. Room heats up quickly to high end of deadband
5. Cycle repeats

It takes time from when the AC turns ON to when it actually starts cooling the air, so your ambient temp is still climbing at that point. Then when the AC starts dumping a bunch of cool air in, it drops it about 10 degrees because there isn't enough heat from the lights to balance/even the drop quickly. Does that make sense?