Oversized mini-split AC

[waltwalt]

So I've got a 12,500 btu mini-split heat pump system for my flowering room which is about 5'x9'. I plan on running two 1000w bulbs in the room with the ballasts and everything else.
The mini-split has 4 settings, feel, cool, dry, and heat. Feel is supposed to be a sort of automatic mode that switches between the other three to keep it approximately 24c with 45% humidity. The other three modes will cool to whatever temperature you set, heat to whatever temperature you set or dehumidify.
The humdity in the room is 80% and roughly 24c, it is an insulated shed outside with a couple holes for intake/exhaust of cooltubes which aren't installed yet.
I've got the drainage hose for the dehumidifier running into my water storage barrel as I planned on using this to top up my water supply.
When I set the unit to dehumidify it starts cooling the room immediately, I'm assuming this has something to do with how it dehumidifies, evaporating moisture or something. The problem with that is that the room is so small that the temperature quickly drops and it drops FAR. I left it on the dehumidify setting overnight to try to keep the humidity down so I could move some plants in; when I got up in the morning and went to check on it, every piece of exposed metal on the unit, from the coils to the lineset, including the lineset outside on the compressor, all had over 1" of frost/snow/ice on it and the room was basically a freezer hovering around 2-4c.

Once I get some heat sources in there will that compensate for this oversizing?

BTW The ambient temperature outside ranges from 16c at night to 30c during the day.

-ww

 

[Phillthy]

i use a 12.5k btu mini and have 3k watts that arent air cooled, a co2 burner and a dehumidifier. the unit never struggles. it does everything i ask it to do. i dont rely on it to dehumidify. i bought a unit just for that. my flower and veg = 8x15x8.

 

[globel]

a true dehumidifier seems like your only true option

 

[Guest 18340]

I have a 9k btu in a 10x5 with two 600 watters (not cooled) and and ballasts. The unit cools the room so quickly that I had no choice but to NOT cool the lights. You MAY be fine with 2 un cooled 1000 watters and the ballasts in their but when the lights go out...
Other than a dehuey, theirs not a whole lot you can do if ultimately the ac is just too powerful for the room size, you can only add so many heat sources.

 

[Guest 18340]

a true dehumidifier seems like your only true option

lol, we were typing at the same time.

 

[squirrelfooker]

Definitely need a seperate dehumidifier. That A/C dehumidifies by cooling down the evaporator coil to the point it will condense the moisture in the air, which means it will also make the room cold. A dehumidifier does the same except it then blows the cold/dehumidified air across the condenser coil which warms it back up. Your mini split condenser coil is outside.

 

[Lazyman]

Yeah I had to put two dehueys in my 20X30 room, and that is with a 12K BTU window AC. The AC only helps with temps a little when it's hot out, the exhaust fans do most of the cooling but yeah, during lights off (daytime) the dehueys and AC all work hard to keep the RH down to 50%. If you're hitting 80% I'm betting you'll either need two units or one big one. I buy used ones off Craigslist for cheap, so I went with two 45-pint ones.

Good idea on using the water from them, as long as you have an overflow fitting on your reservoir that drains outside!

 

[Lazyman]

Oh, and a CO2 generator will add heat, but also more humidity so you will still need the dehumidifier(s).