Help with cooling

[swimman]

So I just installed my 240v 18500 BTU window air conditioner unit in my grow room, having converted it into what essentially is a portable AC. It has a 6" 400 some CFM inline fan helping it.

My problem is synchronizing both the 120 volt fan and the 240v air conditioner unit. I'm concerned about running the inline fan 24/7 as it's a sealed room and I want as little risk of air being sucked out of the room as possible.

Does anyone know of any temperature controllers that run on 240 volt and any inline fans that run on 240 as well? Before, with a shitty portable that vented the CO2 and stank of the room, I had both the AC and the fan hooked up to a sweet temperature controller that ran 120v and worked PERFECTLY. Now, I don't know what the hell to do!

The AC runs more than it has to and its built in thermostat sucks ass, having a large range of where it turns off and on. I'd really like to be able to run both a booster fan and the AC on one controller. I tried using the temp controller with the inline fan and coordinate that with the AC but due to the range the AC runs it just doesn't work. Any advice?

Also first post here, moved from another website that I feel has lost its touch. I hope this place is different!

 

[OldPhart]

One question, if the AC is set to 65 with the fan on high, then you unplug the unit for a while, what happens when you plug it back in? If it comes back on with the same settings, this will be a piece of cake.

I did have one question, what is the inline fan doing? How is the inline fan "helping" it? It may require a bit more work, but I would put the window unit into a box with the face left exposed to cool your room. Then inside the box, put a divider to separate the intake/exhaust. Then vent both the intake and exhaust to the outside. This would be a good place to use the inline fan to boost the airflow, because the internal fan of the AC unit isn't designed to force air through a duct.

I'm assembling a controller when I get all the parts, which should be in by Friday. I was going to document it this weekend, keep an eye out for it. Rudimentary automation is something most grow rooms could benefit from, and it doesn't have to be expensive or unsafe.

 

[swimman]

One question, if the AC is set to 65 with the fan on high, then you unplug the unit for a while, what happens when you plug it back in? If it comes back on with the same settings, this will be a piece of cake.

I did have one question, what is the inline fan doing? How is the inline fan "helping" it? It may require a bit more work, but I would put the window unit into a box with the face left exposed to cool your room. Then inside the box, put a divider to separate the intake/exhaust. Then vent both the intake and exhaust to the outside. This would be a good place to use the inline fan to boost the airflow, because the internal fan of the AC unit isn't designed to force air through a duct.

I'm assembling a controller when I get all the parts, which should be in by Friday. I was going to document it this weekend, keep an eye out for it. Rudimentary automation is something most grow rooms could benefit from, and it doesn't have to be expensive or unsafe.

That's what the inline fan is doing, boosting the airflow through the ducts. It does have an internal memory.

 

[OldPhart]

I had both the AC and the fan hooked up to a sweet temperature controller that ran 120v and worked PERFECTLY. Now, I don't know what the hell to do!

I had miss-read some of your orignal post. All I would do is take the temp controller that you liked, and plug your fan and a slave relay into it. So when the temp controller calls for cooling, it would turn the fan on, and also activate the slave relay. Then all you would need to do is run the A/C through the slave relay.

The parts you would need would be:
A power plug/socket - I would use something like this, and just chop it in the middle.
A contactor - something like this would work well.
A 120v pigtail to go to the temp controller - I would just use any generic power cord that you could chop off some used equipment, or cut the end off a computer power cord, which is my favorite choice.
A box to put it in - this looks pretty decent.
Cable glands - to secure cables going in/out of the box.

So for about 60 bucks, you have a slave relay that can drive pretty much anything you want to hook it to. You might just have to change out the cables/plugs going in/out of it. These things are handy as hell to have around, it changes the way you can control things.... BTW, what I have just described is a basic lighting controller, that you would put between your timer and lights.

Edit: I forgot, you would also need a couple spade terminals to connect the slave cable to the contactor, and some type of ring terminals to connect the grounds to the box.

 

[queequeg152]

keep in mind that most if not all portable ac units will have a delay off feature on the fan .

this keeps the fan running for like 30 seconds while the refrigerant in the evaporator absorbs heat and cools the room.

without this feature that extra capacity would just be wasted.

also remember that on most window units, the thermistor is clipped to the face of the evaporator. it senses the intake air temperature only.

its possible the unit is built with a large deadband too. you dont actually want your ac equipment turning on just to cool like 1 degree of sensible. it would be running too frequently... most house thermostats will do like 2 or 3 degrees, but it can be programmed all the way back to 1 if you want.

its probably not as bad as you think, its just that you are accustomed to a different control scheme.

regarding controlling your fan... oldpharts method would work well enough, but would mean you are power cycling your ac unit on and off.

you could also get a current sensing switch, keep the built in thermostat, and just cycle the fan on and off by monitoring the current flow to the compressor.