3rd AC this week what am I doing wrong?

[U4EA]

put it this way, window a/c units were made for widows for a reason, my guess is the thermostat in the a/c int turning on because of what i had said earlier. if the thermostat doesnt turn on then the compressor will never activate. it all comes down to what i was saying earlier.....but the guy whop said to put your a/c outside and test it in the backyard had a really good idea, if it works in the backyard then im right, if it doesnt then you have a good reason to return your a/c

I really don't think you have a working understanding of A/C's.

Yeah, window A/C's were made for a reason, and that reason is something along the lines of convenience and not having to punch a hole elsewhere in the building. Really has nothing to do with the A/C unit knowing or caring about whether it's inside of an actual window frame, whatever difference that makes. As long as the back side is able to cool itself reasonably sufficiently. (If you can tolerate the heat in the "back" room, the front should be blowing cold. If the back isn't blowing hot at all, well, it's not gonna blow cold out the front either.)

The best suggestion I've seen so far is (besides electrical issues?) to wait a few hours in the correct orientation after transporting.

 

[joe fresh]

^^^the diff im talking bout is if the room isnt 100% sealed(and i mean 100%) then the warm air finds its way back into the grow room and then the a/c is working for nothing, and i dont say this stuff ive been saying because i am a pro with a/c's, cuz im not, i just had this exact same problem when i first started over 10 yrs ago with my first room, a 4kw room, with a 12k btu a/c in the wall, which didnt work so i gave it away thinking it was broken, but the guy i gave it to loved it and it worked fine. so i went and baught a 8k btu and installed it in the window and everything was ok.

so what im saying is out of personal experience and from what the op is saying sounds like hes having the same problem as me

 

[U4EA]

No, it doesn't. If the compressor isn't running, why do you think that it will suddenly run when taken outside? Or put on a window ledge?

Regardless of sealed or not, it should still blow hot out back, cold from front. Did you miss where I said that even sitting standalone in a room, it will still blow cold out the front, and hot out the back?

I have only a basic working knowledge and a light general grasp of air conditioning concepts, as far from "pro" as can be in HVAC. But I know that what you speak of is close to impossible.

 

[joe fresh]

No, it doesn't. If the compressor isn't running, why do you think that it will suddenly run when taken outside? Or put on a window ledge?
.

like i said earlier with the thermostat, the a/c compressor will not turn on unless the thermostat alows it to

 

[U4EA]

Would taking the unit outside or putting it on a window ledge instantly fix the thermostat?

 

[SimplyGreen]

I'm not moving the 25k btu until I have help Friday so that gives me some time to play with it. I would take it outside but it's 220v and I don't have any other circuits to run it to and hauling that bitch by myself is a bitch.

Today I bought a 12k btu and put it in an upstairs window. I'm in a small house and placed a couple 16" fans to direct airflow downstairs. There's also a 12" fan scrubbing air downstairs and the 8" fan cooling the lights. I'm going to add another 8" fan tonight since I have it. I'm also going to use the foam insulation board to box up the backside of the unit to vent it out and direct 16" oscillating fan at the intakes. I'm hoping this might work between the combination of cooler air coming downstairs and the fan getting the air moving more in the lung room.

If all that doesn't work I'm going to have to get rid of the 25k btu unit and get another 12k one and completely vent both of them downstairs with 6" ductwork and in-line fan. I would have just done that today but I'm out of funds for a minute.

 

[U4EA]

I must have missed it or something, 220v huh?

(I forgot that window units > ~15k BTU are 220/240v.)

Are you sure you wired the outlet correctly for 220/240v? It sounds like there could be a possibility of that outlet only giving one hot leg (110/120v). Do you have a tester/meter (non-contact voltage sensor, multimeter, etc)? If not I suggest you go get one. There are some sub-$5 devices at Home Depot you can simply plug into the outlet and it will tell you if you have any wiring faults.

Also describe what happens when you plug the unit in. Do you get anything on the control panel / display? Do you get any audibles (beeps, whatever) when plugging it in or pressing any buttons / turning dials? Does anything work or power on, or is it acting like a door stop?

The more I think about it, the more I suspect it's an electrical issue based on the information available right now (i.e., the 12k BTU @ 110/120v is working).

 

[SimplyGreen]

Well wtf, I just checked it and I'm only getting 120v.

I have 10-2 ran to a 220v 20 amp outlet from a 220v 20 amp two pole breaker. I have it wired the same as my light controller.

I have a ground, a white wire, and a black wire. The way I have it is with the black wire to the breaker, the white wire to where all the other white wires are on the main panel and the ground going to where all the grounds are connected. Is this wrong?

 

[U4EA]

Exactly what I suspected after thinking about it.

The white wire should go to the 2nd hot leg on your double pole (with common trip) breaker.

IIRC, your A/C plug should only have three prongs (two flat blades and a round ground). If it has four prongs (three flat + round ground), then you will need a 3-conductor cable (like 10/3, but 12/3 should be good enough for your application unless it's a long run; do you have a multimeter to measure voltage drop?)

Get ready for cold air! (And hot air from the back.)

 

[SimplyGreen]

It's working! I have to smile at all I went through for such an easy fix. All of your input was greatly appreciated.

So does that mean the light controller isn't wire properly as well? It's wired the same as I described but has been working just fine.

 

[U4EA]

Excellent.

Do your ballasts auto-switch from 120v to 240v w/o any rewiring or switching receptacle plates? If so, they're running at 120v and that's why they're working. Problem with that is, if you sized your wire for the amperage draw @ 240v, you're overloading your wires and playing with fire...

I find that most ballasts/etc are slightly more efficient @ 240v, but typically a very negligible difference and not the reason to go 240v. (Balancing loads is a better reason.) Nothing wrong with running @ 120v, just might cost you a tad more on installation ("wasted" copper on neutral, etc.)

 

[SimplyGreen]

If I have a fire hazard I'd like to get on that pronto.

I have a 240v 40 amp breaker wired to a CAP MLC-8 running 7 600w galaxy ballasts with 240v cords.

This is wired in the same way that I described the AC being wired. Is this not correct?

I'd imagine I'd blow the breaker if running 4200 watts on a single 20 amp 240v breaker.

 

[U4EA]

Right now you're running @ 120v, and if you used #8 wire that will not be enough to safely carry 4200w (max. based on 80% is 3840w @ 120v). I'll bet that wire (if #8, again) is running a bit higher than "warm" after running the lights for a little while.

If you used #6 (just enough, max. safe capacity = 4800w @ 80%) or larger, it should be fine, but know that all your lighting load is on one leg by default. Meaning that if you choose to continue lighting @ 120v, you should work on balancing your loads. You can do this by either re-wiring your MLC8 so that one contactor is on one hot leg, and the other on another hot leg (with the white wire running back to the neutral bar), and remove the daisy-chain wire between the two contactors. Or put all of your other devices' breakers on the other leg. Also know that if using #6 or larger @ 120v, you will need to reconfigure the wiring if you want to plug more lights into that controller.

Unless your Galaxy ballasts have two cord receptacles (one for 120v, one for 240v), I'm guessing that it automatically detects voltage and operates accordingly. The only real difference between the 120v and 240v cords are the physical orientation of the 2nd blade to avoid accidental plugging into a 120v outlet and vice versa. Using a "240v cord" on a 120v outlet will look no different to the electrical device as using a "120v cord".

Since you already have the wire, I wouldn't bother getting a #6 or two separate runs (the MLC8 should have two separate 30A contactors, daisy-chained by default) for 120v application. Easiest and "best" thing to do is simply switch the white wire in your panel from the neutral bar to the hot leg of your DP 40A breaker. Just like you did with your A/C. The ballasts @ 240v does not need a neutral wire.

If there's any chance that you're a super stoner and will forget what you did today, I might be inclined to tell you to get some red electrical tape and tape the white wire (near the stripped ends) to make it super-clear. But I personally don't think it's necessary.

In short, switching to 240v might save you some money, time, and a little bit of heat/voltage drop. It will also "future-proof" your setup a bit better. Speaking of future-proofing, if you have #6 wire or larger, it might not be a bad idea to swap out that DP 40A breaker with a DP 50A breaker. That will allow you to get the maximum future capacity out of your MLC8, rather than having to get another breaker later down the road if you want to plug in more watts.

I don't mind answering more questions, but to keep the scope of the thread intact, I suggest you check out the growroom electricity & wiring thread (stickied in the GD&E subforum) if you have any further questions or issues. There are some knowledgeable real electricians (and not a hack-job like me) that will be glad to help you, especially with your attitude. Plus, it may help others down the road in that thread.

 

[Kalicokitty]

I must have missed it or something, 220v huh?

(I forgot that window units > ~15k BTU are 220/240v.)

Are you sure you wired the outlet correctly for 220/240v? It sounds like there could be a possibility of that outlet only giving one hot leg (110/120v). Do you have a tester/meter (non-contact voltage sensor, multimeter, etc)? If not I suggest you go get one. There are some sub-$5 devices at Home Depot you can simply plug into the outlet and it will tell you if you have any wiring faults.

Also describe what happens when you plug the unit in. Do you get anything on the control panel / display? Do you get any audibles (beeps, whatever) when plugging it in or pressing any buttons / turning dials? Does anything work or power on, or is it acting like a door stop?

The more I think about it, the more I suspect it's an electrical issue based on the information available right now (i.e., the 12k BTU @ 110/120v is working).

Wow bro, good call.
Always like to see problems solved, it's what the boards supposed to be about, helping each other.

Good deal!
Enjoy the cold air!

 

[SimplyGreen]

Indeed I will.

I also changed the wiring on the light controller.

Muchos gracias U4EA