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thermostat question

hotenuff4u

hotenuff4u

Anyone had any experience hooking thermostats up to box fans, or know of any good sites i should check out?

Building a greenhouse about 5 miles from my house in my moms back yard but will probably only be able to visit it once/day, so I'm just thinking I'll prob want any climate control to be governed by thermostats......

Insights and criticisms welcome :lol:
 
Google is your friend! There are thermostats that plug into an electrical outlet then can run to a heater/AC/fan to turn it on or off. But trust me, a fan alone will not work. See the "Started on my greenhouse" thread. I highly recommend a remote thermometer if you have someone who can open/close a door. I left today to 10 am - the outside temps were in the lower 40s and it was quite cloudy. Too cold to open the door. Got back at 2:30 - the sun was shining brightly and the inside temp was 125. I have a few fried green tomatoes. If you do not have someone who can check the temps, then invest in an automatic vent that opens and closes depending on the temp.

Mike
 
Short answer- RTFM! :rofl:
Kidding- but yeah, the manual is best, although technical. Try googling A419 thermostat- the A419 is used by beer abusers, snake growing weirdos, greenhouse operators, and every store and bar.

I have a thermostat controlled exhaust fan in my greenhouse. I also have a normal box fan that's up high blowing air down, circulating the hot air down. The box fan is on a timer so it comes on during the day, shuts off at night.
The thermostat used to control the exhaust fan appears to me to be a standard household thermostat, intended for electrical HVAC (I'm not at home at the moment so I don't have the make or model number). The exhaust fan is in the peak, and it has louvers to keep it sealed when not in use. I don't know the exact dimensions on the fan itself but I'm pretty sure it's a 12". A couple days ago, with the exhaust fan turned off and full sun on the greenhouse, I had 120°F while ambient outside was 39°F. I turned on the exhaust fan, with the thermostat set to 70°F. Within 30 minutes the thermometer was reading 70°F. A 12" fan will totally exchange all air in a small greenhouse literally within a matter of minutes, and will bring a greenhouse down to ambient temperature.
I would recommend a Johnson Controls A419 digital thermostat. They are cheap, programmable for both range and span, they have a remote thermoprobe for more accurate temperature reading, and super easy to wire up into ANYTHING, either for heating or for cooling. I also have one on my kegerator :lol: You could poorboy it and try to score an old/cheap/free/maybe still working electrical home thermostat like what I've currently got, but I wouldn't recommend it. Do it right, do it once, don't burn down the house.
I would also recommend a standard 10" or 12" industrial exhaust fan- they come pre-mounted into a frame that contains the louvers, and they're extremely easy to install. Wire the thermostat inline and you're done.

About $55 for the A419 and I bet you could pick up a 10" or 12" locally for about $100-$150. Expensive I know, but it is definitely the one part of a greenhouse you need to spend money on- one hot day can kill everything.
 
If you are not onsite, consider these oil-filled piston vent openers. They react to the heat inside the greenhouse, more heat expands the oil in the piston and opens the vent wider.

I saw one of these at a local market, but have never used one myself. Over the course of the morning, as the sun got hotter, the vent opened wider. It was kinda cool!

I cannot vouch for the quality of any of these products, I'm only linking them for folks to look at. One site has them starting at $49. Pretty reasonable if someone is spending the $$ to build a greenhouse.

I googled "greenhouse automatic vent opener" and got lots of hits-

http://www.littlegreenhouse.com/accessory/vent2.shtml

http://www.charleysgreenhouse.com/3515-Univent-Automatic-Vent-Opener.htm


Then, if you felt it was still necessary, you could still put a fan on a plug in timer, or plug in thermostat.

hope to see pics of your project....
 
hotenuff4u said:
T118P from littlegreenhouse...purchased, and littlegreenhouse bookmarked, badass site, thanks
Click to expand...

No prob. I have only had the T110 for about a month and a half now, but I have no complaints. I have a thermometer inside my grow box and, based on the temps, it seems to operate accurately.
 
yesssireeee, i put that bad boy on heat mode running to a heater underneath a jiffy greenhouse seed starter, set at 80 degrees and it works perfectly!

the timing is perfect, my greenhouse should be done around the time the outside temps are up and my seeds should be healthy baby plants by then too! I'll put my thermostat on cool mode and hook it up to my greenhouse fans, and i'm ready to go for a badass growing season!
 
I'm guessing your already have this taken care of but I thought I might chime in a second on a nice temperature controller that Hinky recommended. I also brew beer (a "beer abuser" according to Hinky :) ) and like to keep the temperature consistent during fermentation for quality product and I use the Johnson Controls A419. I have it set up to a heat wrap around a 6 gallon carboy. What's great about it is that you can switch it to heating or cooling mode, get precision within 1 degree and also set the differential where it turns on and off.

Hinky I have to ask, where the hell did you score that for $55?! I paid $80 :( .
 
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