A/C unit for ferm chamber - no cold air.

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ThreeTaps

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Well, I turned the window A/C unit on (Daewoo dwc-058rl) in my fermentation chamber to test it 48 hours before actually using it with a brew, and the A/C compressor turned off after about 10 minutes. The temp got down to 66F, then the compressor turned off and it's been blowing regular air for over an hour now. I have it set at 60F (lowest it will allow me to set it) but it doesn't get below room temp 68F as only the fan is on, not the compressor.

The A/C unit is on top of a garage closet, and the sensor wire lead was lengthened to 6'. The sensor does work accurately, as it detects cold refrigerator temperatures as well as hotter temps when I hold it in my hand.

Any ideas?
 
Find the AC's temp probe and heat it up between your fingers. If that doesn't turn it on, your compressor might be dead. Is it new or used?
 
Find the AC's temp probe and heat it up between your fingers. If that doesn't turn it on, your compressor might be dead. Is it new or used?

I tried that before, and it does show the temp rising but doesn't turn the compressor on. It was bought new 2008 summer, and only used for a couple of months in the hot season.

I'm going to set it at 65 and see if that does anything. Maybe they have a low threshold set lower than it can actually go. Not likely, but worth a shot.

EDIT: Nope, nothing. Even turning it on turbo mode (no temp threshold, just constant cooling) didn't turn the compressor on. Ugh.
 
That does not sound good. Can you see if there is ice build up on the coils? and has the water trap been drained? May be try draining the condensation trap and turning it off over night.

did you turn it on less than 24hr after installing it? I've always heard that if you move a refrigeration system excessively, or tip it on its side, that you should give it 24hr before turning it back on.

Luckily its fairly cool right now, you might not need the ac to hold a good temp, that room you build might be adequate to hold a stable 68º. If you need it though, I have some room in my freezer chest's I can offer you.
 
I bypassed the whole tstat and just hardwired the ac so that the compressor is on if juice is flowing to it.

My temp control is based completely on the external t-stat.
 
Thanks for the replies. I don't think it's condensation or the coils freezing up, as this is the first time it's been on for longer than 30 minutes in over a year.

I guess I'll just have to start shopping around for another one.
 
Couple questions are is there freon in the system 2 there should be high and low pressure switches on it check to make sure they aren't open I.e. Show OL on your multimeter set to ohms last one and its really obvious and happened to me before but is there power to your compressor
 
Couple questions are is there freon in the system 2 there should be high and low pressure switches on it check to make sure they aren't open I.e. Show OL on your multimeter set to ohms last one and its really obvious and happened to me before but is there power to your compressor

Thanks for the reply, but I have no idea how to check the freon in a window A/C unit. As far as checking for the high/low switches and all that other stuff, again don't know where to look. I would assume that since the unit powers on and the fan continually runs that the compressor would have power to it as well.
 
I would reverse the sensor lengthening process to see if that is somehow shorting something out. I had a similar problem with my wine fridge conversion to kegerator recently. I bypassed the thermostat (very simple in this fridge) and it works perfectly, so far!
 
I would reverse the sensor lengthening process to see if that is somehow shorting something out. I had a similar problem with my wine fridge conversion to kegerator recently. I bypassed the thermostat (very simple in this fridge) and it works perfectly, so far!

Good idea, but it's such a simple wiring job that I doubt it's the culprit. Just a two stranded wire connected to the same type of extension wire (slightly larger awg). Plus, if I shorten the lead, then it mitigates the whole purpose of having an A/C unit up top.

I'm looking on craigslist right now for a good price on a portable A/C unit that I can just put on the floor of the fermentation cabinet, then just direct the exhaust hose out the top.
 
Portable AC units aren't known for efficiency...

Sounds like you're using the built in thermostat and reading the temperature the AC states it is. Correct?

If that's the case I'd try bypassing the thermostat so that if the AC is on the compressor is on. See if that gets you down to temperature. If it does, toss on an external thermostat.

Reminds me: I need to do a writeup on the $10 external thermostat from home depot...
 
Portable AC units aren't known for efficiency...

Sounds like you're using the built in thermostat and reading the temperature the AC states it is. Correct?

If that's the case I'd try bypassing the thermostat so that if the AC is on the compressor is on. See if that gets you down to temperature. If it does, toss on an external thermostat.

Reminds me: I need to do a writeup on the $10 external thermostat from home depot...

I'd love to try this, how do I bypass the thermostat so the compressor is always on? The manual for the unit isn't to be found anywhere, not to mention the maintenance diagrams. That would be a fantastic solution.
 
Good idea, but it's such a simple wiring job that I doubt it's the culprit. Just a two stranded wire connected to the same type of extension wire (slightly larger awg). Plus, if I shorten the lead, then it mitigates the whole purpose of having an A/C unit up top.

I'm looking on craigslist right now for a good price on a portable A/C unit that I can just put on the floor of the fermentation cabinet, then just direct the exhaust hose out the top.

I think he mean that you should undo this wiring mod and put it back the way it was , as a troubleshooting step , just to determine if it is at fault.
 
When you turn your "temperature" knob can you hear it click once it gets to your room temp? There's also the obvious thing of making sure your settings are correct.

Compressors do die, but usually after many years of service. I also back up the the suggestion to bypass the thermostat. It is really quite easy; it's a one wire in one wire out kinda thing on 99% of ordinary analog window ac units.
 
It appears as though theres hope yet. I took the unit down, put it on my workbench and plugged it in. Turned it on, the compressor kicked in when re-setting it to 60F. I then put the sensor up to it's air port, and it got down to 63F per the sensor then the compressor shut off. Rose again to 65F, compressor never turned back on. So I took the housing off to look at its guts, turned it on again and this time left the sensor on the floor. The compressor has been on for a good 3 minutes now, blowing real cold air out. So, the compressor is good, but it seems as though something is tripping it to turn off.

I'm still willing to bypass the temperature sensor and get an external one, so here's an image of the wiring going on. This is what I see:

Power lead: Green (ground), Black, White
Compressor: Black, White, Red
Fan: Black, White, Yellow, Orange

FYI: The compressor has now been on for about 10 minutes, while on my workbench.
Also, the compressor wires are the one's in the black insulation coming in from the right side of the image, and the power wires are coming in from the bottom. The fan wires are connected to the 4-wire connector.

EDIT: After nearly 15 minutes of the compressor on, I picked up the sensor and put it up to the cold air area and the compressor shut off since it detected the temp as 58F. I then held the sensor in between my fingers, it rose to 74F but the compressor never turned back on. Same thing happens if I unplug it then plug it back in from the power outlet. Turns on again, with the compressor, but shuts off and doesn't come back on (compressor) once it reaches target temp the first time.

IMG00147-20091009-0826.jpg


IMG00146-20091009-0825.jpg
 
The wiring diagram is right there in the photo you posted. You use that to determine what you need to do to bypass the tstat.

I have never heard of anyone attempting to run an ac for this purpose without bypassing this tstat. Largely for the reasons you're experiencing. Luckily bypassing the tstat and adding an external one is easy.

On digital ac's like mine (and yours too, yes?) I had to bypass the entire control system and just hardwire the fan and compressor to the external tstat. Luckily this works well and looks good too since now I have the temp control on my fridge mounted on the front of the fridge.
 
On digital ac's like mine (and yours too, yes?)

Yep

I had to bypass the entire control system and just hardwire the fan and compressor to the external tstat. Luckily this works well and looks good too since now I have the temp control on my fridge mounted on the front of the fridge.

I'm great with computers and car engines etc, but I havn't worked too much with wiring.

On first guess, there are three black wires going into the digital control unit. One is the power lead, one is the compressor lead, and the other is from the fan lead. Would I simply unplug them and connect them all together? There is also a yellow and white lead coming from the fan going into the digital control unit, I would presume for fan speed control, power saving mode, etc. Would I just cap those off?

FYI: I'm envisioning an external tstat that I would actually plug the A/C unit into using the power cord, unless this isn't the best way to do it? I would like to see the writeup on that $10 external tstat home depot DIY unit mentioned above.

I really appreciate the help, by the way.
 
Without looking at the wires that sounds about right. It took me a while looking at the tiny little wiring diagram and the actual wires to figure out what to do. And I'm in the same boat as you. I've got some basic wiring knowledge and used that to do this. Someone with more advanced knowledge might have have been able to do without completely bypassing the internal controls. But mine works so I'm not complaining.
 
Can you post a clean pic of the wiring diagram. i might be able to help you out. Also i live in Clairmont, so if you need help with the wiring let me know.
 
I wonder if it has a Anti Short Cycle delay built into the unit? If that's the case then it would wait until that time period before letting the compressor come back on. You would want to bypass that along with the thermostat if they were not one unit.
 
I agree that you might want to let a little more time pass between "cooling demand" cycles. The controller might have a built int ASD of 10 minutes to prevent compressor fatigue and ice buildup on the coils.
 
I agree that you might want to let a little more time pass between "cooling demand" cycles. The controller might have a built int ASD of 10 minutes to prevent compressor fatigue and ice buildup on the coils.

I left it on all night and it never kicked back on, stayed at room temp.
 
Allrighty, I'm a chemical engineer, so I'm not cut out for this crap....electrical engineers speak up!

Why the hell does a capacitor have THREE wires?

Seems like white of compressor and fan go to white of the plug, and black of compressor and fan go to black of the plug, and get rid of the PCB, tstat, and capacitor....but that leaves you with extra wires, so I dunno.
 
OK, so follow me on this:

Compressor:
White shares a common cap post with plug-white, so white to white is right there.
Black on the compressor runs to plug-black through Relay 1, so black to black is right there.
Red goes to the other post of the cap. Hmmm.....so If I remember right, a cap in series of an A/C circuit acts as a surge suppressor.....but where does the red wire go to?

For the fan, hell, I'm lost, but how hard is it to screw up a fan? Just try black and white first, (tap them together, if it arcs and the fan doesn't kick, you are shorting it, try different wires on the fan until it kicks. Only worry about white and black from the plug...green is ground, that's only there for your safety, and who cares about that?...if it does kick, those are the right wires)

Someone with a better understanding of this should really speak up! lol. :ban:
 
I have a newer Daewoo A/C unit (DWC~05320MEC) and it definitly has a short cycle protection feature. I believe it's 2 minutes. If I turn it off or adjust the target temp up, the compressor won't kick on again until enough time has elapsed. I don't know if this info helps at all, but I thought it could be useful.
 
OK, so follow me on this:

Compressor:
White shares a common cap post with plug-white, so white to white is right there.
Black on the compressor runs to plug-black through Relay 1, so black to black is right there.
Red goes to the other post of the cap. Hmmm.....so If I remember right, a cap in series of an A/C circuit acts as a surge suppressor.....but where does the red wire go to?

For the fan, hell, I'm lost, but how hard is it to screw up a fan? Just try black and white first, (tap them together, if it arcs and the fan doesn't kick, you are shorting it, try different wires on the fan until it kicks. Only worry about white and black from the plug...green is ground, that's only there for your safety, and who cares about that?...if it does kick, those are the right wires)

Someone with a better understanding of this should really speak up! lol. :ban:

Well, I was able to get the fan spinning at full speed with all three white wires connected, and all three black wires connected, and the yellow wire connected to the whites (fan wouldn't turn on without that yellow wire attached to the white wires). However, I can't get the compressor to actually power up. I'm thinking the red wire has something to do with it, but it hasn't budged when connected to the orange wire, the white wires, or the black wires. In fact it stops the fan from going when connected to the black wires.
 
I have a newer Daewoo A/C unit (DWC~05320MEC) and it definitly has a short cycle protection feature. I believe it's 2 minutes. If I turn it off or adjust the target temp up, the compressor won't kick on again until enough time has elapsed. I don't know if this info helps at all, but I thought it could be useful.

Thanks, but I left mine on all night and I couldn't tell that it kicked on. It at least never got the chamber to its target temp, or anything below room temp.
 
I wish I could see inside mine to get a point of reference but I connected three wires in and two wires out bypassing the circuit boards but including the capacitor in the circuit. It was more obvious to me just following the wires coming in. Once I cut the boards out of the circuit everything was wired on and used a piggback on the ext. tstat.
 
What if you keep the capacitor in the loop:

Plug-White -> Capacitor ->compressor white -> blue wire -> fan white
Plug-black -> compressor black -> fan yellow and fan black, (I think you are shorting something with yellow to whites...)
compressor Red -> capacitor
Fan orange -> capacitor

That takes out the PCB but keeps the capacitor and all the connections...
 
Single phase motors need something to help them start, usually a Cap. the motor will have a centrifugal switch that bypasses it when at speed.

All of the controlling is done electronically by the Power Control board (PCB) so if you shunt the compressor starting relay you could bypass all the safeties, including the thermal overloads. does the Compressor have any kind of "reset" button on it? or any thing that says Thermal Protection on it?
 
Sounds right Shorty.

Lazy, exactly that PCB is nothing but a menace that keeps us from doing what we want. For whatever reason that PCB is throwing out a command to the compressor to not run. Put this sucker on a GFI circuit and external tstat and if you kill the compressor quicker it is still 1/10th the cost of an actual two part refrigeration unit.

My 10K BTU unit cost me $129 brand new and it maintains a 30-35 differential to ambient without even getting warm. It runs maybe 7 minutes once an hour.
 
Single phase motors need something to help them start, usually a Cap. the motor will have a centrifugal switch that bypasses it when at speed.

All of the controlling is done electronically by the Power Control board (PCB) so if you shunt the compressor starting relay you could bypass all the safeties, including the thermal overloads. does the Compressor have any kind of "reset" button on it? or any thing that says Thermal Protection on it?

Woohoo! So that's why the cap is there!

Well ,we know the PCB isn't controlling the capacitor circuit to the compressor, because it's not in the loop. The only action the PCB has on the compressor is turning it on and off with the relay.

The fan, on the other hand, has too many wires going into it. But I maintain that it's just a friggen fan, and you just CAN'T eff those up.
 
Hey, by the way Justin, be careful with this crap, eh? 120 volts at 15 amps is nothing to be trifled with, (well, trifle away, but do it in a way that won't electrocute you).
 
Here's how I've been able to make it work so far, however the fan is having some difficulty getting going.

-All black wires together.

-Plug white wire, Fan white wire, capacitor (plug white wire connector lead), Fan yellow wire, all together.

-Compressor red to capacitor

-Fan orange to capacitor

-Blue unconnected

As I said, the compressor turns on and everything seems fine, except the fan itself kind of slowly rocks back and forth like it's trying to move. It will then move either forward or backward, whichever way it gets a bigger "kick" during the rocking back-and-forth motion. If I give it a little nudge forward (or backward too), it will feed off that motion and continue as intended to a strong spin.
 
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