My A/C is broke

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Therookguy

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Therookguy
Hello I have an R182 from the 80's with an, convenient for hot summer months, A/C. When I first purchased the plane the A/C worked, not great, but it made enough of a difference. I don't like sitting in a swamp when I fly so I was hoping to get it fixed.

Here's my dilemma. MX is generally expensive and, per all the Savvy MX videos I've watched, I'm afraid to rack up a 5k bill for MX that isn't related to airworthiness.

Right now the blower motor runs (it's actually more powerful on the low setting) but no cooling is occurring. As a MX limited person I have few guesses: The A/C needs more coolant, the switch to turn it on is broke, a belt is broke somewhere, or the A/C is just plain broke.

So what can I try myself before I bring it into mx? Can I grab an A/C refiller bottle from the autoshop and try to restore the coolant or is it more complicated than that?

If I do bring it into the shop what should I tell them so we don't end up doing 2k worth of shotgun MX without fixing the problem?
 
Good luck finding a shop that knows refrigeration...It's probably an R-12 system.o_O
 
If it is low on refrigerant, it is because it leaked, filling it will not help that. The leak needs to be fixed.

DO NOT buy a can of refrigerant and dump it in. The leak needs to be fixed, the system needs a good vacuum pulled, and then it needs to be refilled by weight with the proper equipment (gauges and a scale). If you do not have the knowledge and equipment to do this, you’re by far more likely to cause more damage than fix anything.
 
I agree with jesse above.

I think it is electrically driven, no belt.

I would take a set of AC gauges and see if you still have any pressure in the system with the motor off. My bet is no. Many times it leaked out and is why it stops cooling. Like said the leak needs to be found and repaired. Then pull a vacuum to insure no leaks. R-12 makes it more complicated since we switched our equipment to R134 many years ago. Got to find a shop who does aviation AC work.

I know I would want it fixed also if it was my plane. Friend of mine just had his system removed off his cheerokee instead of having it repaired under the advise of the local AP mechanic.

Do not use a stop leak in your refrigerant, very bad for the AC gauges and recover machines used to service AC systems. Good luck with it.

https://www.blueskiesaviation.aero/aircraft-ac-and-oxygen-services

https://www.google.com/search?q=avi...3i22i29i30.13448j0j4&sourceid=chrome&ie=UTF-8
 
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In a car, it's relatively easy to do basic troubleshooting yourself. You can determine things like if the compressor is spinning, is there refrigerant in the system, is a belt off, things like that. With cowling and things like a giant meat cleaver spinning around, it's probably better left to a mechanic.
 
PaulS said:
In a car, it's relatively easy to do basic troubleshooting yourself. You can determine things like if the compressor is spinning, is there refrigerant in the system, is a belt off, things like that. With cowling and things like a giant meat cleaver spinning around, it's probably better left to a mechanic.
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I always though the fan blades on a car were dangerous when working on a running car.
The propeller on a plane is a whole new ballgame to me! Pretty hard to see things under the cowl while the motor is running, out right dangerous on a plane! I won't go anywhere near a prop that is spinning.
 
PaulS said:
In a car, it's relatively easy to do basic troubleshooting yourself. You can determine things like if the compressor is spinning, is there refrigerant in the system, is a belt off, things like that. With cowling and things like a giant meat cleaver spinning around, it's probably better left to a mechanic.
Click to expand...

:yeahthat:

If you know nothing about Air Conditioning then call a mechanic. It may be something as simple as the clutch on the compressor not engaging for various reasons.

As noted above if the refrigerant is low there is a leak that needs to be fixed and that takes someone with tools and experience to diagnose and repair. I agree the system likely uses R-12 but there might be a procedure to convert it. If you don't know how to fix it ... trying to do so may cost you well more in the long run.
 
I'd say just dump some refrigerant in there and see if it works. May lub up a seal and you get lucky and work for a period of time. Like until the end of August. Use the big can they sell for car refrigerant it comes with a interface/fitting for the low pressure side with a built in gauge.
 
Looks like I'll have to find it and figure out what type of A/C it is first.
 
6t6 said:
I'd say just dump some refrigerant in there and see if it works. May lub up a seal and you get lucky and work for a period of time. Like until the end of August. Use the big can they sell for car refrigerant it comes with a interface/fitting for the low pressure side with a built in gauge.
Click to expand...

All he can get to "dump" these days is R-134. If the refrigerant in his system is R-12, they aren't compatible. Get a mechanic that knows what they're doing.
 
6t6 said:
I'd say just dump some refrigerant in there and see if it works.
Click to expand...
Uh, no. It might be all it needs, but you don't know what you don't know, like what kind of refrigerant it takes or how much weight of it should be in there. If you overservice it — it could blow up in your face and freeze your eyeballs. Or kill you. :eek: Besides, you don't have the proper equipment and know how to use it, or you wouldn't be here asking what to do. The system probably should be evacuated to see if there's a leak and then the proper weight of refrigerant added only after any leaks are fixed. I'm not an expert, but I just spent about a week fixing and learning about A/C on my car. Stay away from those single gauge quick-shot setups. Find a mechanic with real manifold gauges and A/C certification. IMO.
 
It doesn’t have to cost 5k to troubleshoot it. Have a mechanic look at it.
Is there anything Wrong with having a mechanic that works on aAC systems that is an auto guy?? The systems have to be pretty similar. Might be able to troubleshoot it faster and give direction to your A&P to a faster fix.
 
Do they still make "chill pills?"
 
I'll have to go look at my actual POH and see what type of A/C and where it is etc. Once I do that I call a mechanic and see what they say. I'll let ya'll know if it ever gets fixed...
 
Rednecks like me would probably take the cowling off and have a look see. If the fan is working and the compressor kicking in, it is very likely low on Freon. If it is indeed electrically driven, you would not have to have the meat chopper spinning. If the compressor is not kicking in, get out your checkbook. If everything is running, then get an AC tech to check it out.
 
somorris said:
Rednecks like me would probably take the cowling off and have a look see. If the fan is working and the compressor kicking in, it is very likely low on Freon. If it is indeed electrically driven, you would not have to have the meat chopper spinning. If the compressor is not kicking in, get out your checkbook. If everything is running, then get an AC tech to check it out.
Click to expand...

FWIW ... in many systems the compressor may not come on if the freon level is low.

I'm used to experimental airplanes so I'm with you ... I'd go have a look-see under the cowling but I can't recommend that for a certified aircraft owner that seems to know very little about how an AC system works. Call the mechanic.
 
There is a very good chance a qualified person can fix this by replacing a 25 cent o-ring and then properly refilling. Dump a bunch of refrigerant in without knowing what you're doing and that is precisely how you end up with a $5,000 (or more) repair bill.
 
If this were mine. First thing to check is the refrigerant level....PSI (not running)....if there's enough pressure (60-80 psi) I'd try and run the system and measure operating pressures. Then look for an electrical issue....clutch, pump, etc...

If the system is low....most likely... look for any oily spots at hose connections and seals (especially pump seals). Then pressurize with nitrogen to 300 psi and begin looking for leaks with soapy water. (most probably IMHO)
 
Daleandee said:
I have no idea how/if these do what they say the will. A real mechanic will have a real one but in the interest (pun not intended) of saving money:

https://www.harborfreight.com/elect...MIjr6IhoCS-AIVN_fjBx0Lfw2ZEAQYBSABEgJnUvD_BwE
Click to expand...

Those work pretty well if there is refrigerant in the system. But he really needs to start more basic that that. Like, is the compressor working, fuses, wiring, switches. Once that stuff is known good, then ideally hook some gages up to it and check refrigerant levels. If that is low, then find the leak and repair. Cars are pretty simple, and you can buy the refrigerant for the newer models. The thing is you need basic knowledge of refrigeration and what to do once you get the leak fixed to get the system working again. That involves the gages, a vacuum pump and refrigerant. If it's R12, it's basically illegal for someone uncertified to buy that refrigerant. So there is that too.
 
Yup. My finger is freezer burned. o_O

I took the type I online then later decided I needed more. I went and sat for the universal. You can do practice tests till you know enough….just like any other gummint test.
 
PaulS said:
Those work pretty well if there is refrigerant in the system. But he really needs to start more basic that that. Like, is the compressor working, fuses, wiring, switches. Once that stuff is known good, then ideally hook some gages up to it and check refrigerant levels. If that is low, then find the leak and repair. Cars are pretty simple, and you can buy the refrigerant for the newer models. The thing is you need basic knowledge of refrigeration and what to do once you get the leak fixed to get the system working again. That involves the gages, a vacuum pump and refrigerant. If it's R12, it's basically illegal for someone uncertified to buy that refrigerant. So there is that too.
Click to expand...

Agreed on all points. I was referring specifically to the Harbor Freight "not made in America" freon sniffing tool as to how well that one worked. There are high quality ones that I know work extremely well.

I'm with you on the diagnosis but it seems the OP isn't skilled on AC systems. I've suggested already that they call a mechanic as I think that's their best approach. Most auto AC guys would know their way around this system.

Years ago when converting a vehicle from R-12 IIRC the only things that had to be done was replacing the o-rings on all the connections, using a different compressor oil, and resetting the compressor cycle switch (some are not resettable and must be replaced). Of course that included a vacuum down and leak check. That was a long time ago & I'm likely forgetting some of the process.
 
6t6 said:
I'd say just dump some refrigerant in there and see if it works. May lub up a seal and you get lucky and work for a period of time. Like until the end of August. Use the big can they sell for car refrigerant it comes with a interface/fitting for the low pressure side with a built in gauge.
Click to expand...

If the system is an older R12 system, this is really bad advice *unless* OP has access to R12 (which is unlikely). Mixing R12 and R134a (the most common auto store refrigerant) (a) is illegal, and (b) likely will cause all sorts of damage to the system. More information here: https://vehiclefreak.com/what-happens-if-you-put-r134a-in-an-r12-system/
 
Gary Ward said:
I agree with jesse above.

I think it is electrically driven, no belt.

I would take a set of AC gauges and see if you still have any pressure in the system with the motor off. My bet is no. Many times it leaked out and is why it stops cooling. Like said the leak needs to be found and repaired. Then pull a vacuum to insure no leaks. R-12 makes it more complicated since we switched our equipment to R134 many years ago. Got to find a shop who does aviation AC work.

I know I would want it fixed also if it was my plane. Friend of mine just had his system removed off his cheerokee instead of having it repaired under the advise of the local AP mechanic.

Do not use a stop leak in your refrigerant, very bad for the AC gauges and recover machines used to service AC systems. Good luck with it.

https://www.blueskiesaviation.aero/aircraft-ac-and-oxygen-services

https://www.google.com/search?q=avi...3i22i29i30.13448j0j4&sourceid=chrome&ie=UTF-8
Click to expand...


What do you mean “electrically driven”? If you mean the compressor is driven by an electric motor I would suspect that motor would have a large current draw. Can you explain what you meant by that?
 
RonP said:
What do you mean “electrically driven”? If you mean the compressor is driven by an electric motor I would suspect that motor would have a large current draw. Can you explain what you meant by that?
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Exactly what you would think, a compressor driven by an electric motor. As far as current, probably about 50 amps to start the compressor and maybe 30 to keep it a turnin.
 
jesse said:
Exactly what you would think, a compressor driven by an electric motor. As far as current, probably about 50 amps to start the compressor and maybe 30 to keep it a turnin.
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In aircraft equipped with an electrically driven compressor is the alternator also upgraded? Do you know what GA aircraft employed an electrically driven compressor?
 
RonP said:
In aircraft equipped with an electrically driven compressor is the alternator also upgraded? Do you know what GA aircraft employed an electrically driven compressor?
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Most all the STCd AC packages use an electric compressor. Yes the alternator is upgraded. It is easier to upgrade the alternator than it is figure out where/how to mount and drive a compressor directly from the engine.

As to the OEM installs that came with the airplane, not sure how many are electrically vs engine driven.
 
jesse said:
Most all the STCd AC packages use an electric compressor. Yes the alternator is upgraded. It is easier to upgrade the alternator than it is figure out where/how to mount and drive a compressor directly from the engine.

As to the OEM installs that came with the airplane, not sure how many are electrically vs engine driven.
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Jesse,

Thanks for the info. That is really cool both figuratively and literally! With a lot of assumptions the alternator load on the engine would be about 1/2 horse. A 150 engine would barely notice that even at 75% cruise power. It makes sense to upgrade the alternator and mount the electrical compressor where ever there is room, even under the back seat of a typical Cherokee 140. Just have to figure out air flow for the condenser and how it affects W&B. After your info I looked up one unit and it uses a brushless motor. Brushless motors are very efficient since they can adjust to the lead/lag voltage and current variations at RPM always running at peak efficiency with little electrical losses. Thanks again.
 
If you can't afford to fix your A/C then you need to get out of the airplane business. I know it's not cheap but no matter what kind of system you have there are basic trouble shooting steps that have to be done period. Airplane systems aren't the place to be experimenting or shot gunning parts. Even if you have it removed you will have to engage a mechanic to do it and recompute your weight and balance data. I am an A&P and if you remove it and bring it to me for a logbook entry I'll just laugh and tell you to keep looking for another sucker.
 
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6t6 said:
I'd say just dump some refrigerant in there and see if it works. May lub up a seal and you get lucky and work for a period of time. Like until the end of August. Use the big can they sell for car refrigerant it comes with a interface/fitting for the low pressure side with a built in gauge.
Click to expand...
IF you can get the refrigerant required. My house has a unit that uses R-22; when I bought ten pounds of it, the price was nothing short of spectacular. It's come back down as demand has dropped due to replaced units (and people pumping in propane!)
Genuine R-12 (left-over stuff) can go for fifty bucks a pound. The replacement stuff surely isn't approved for this use.
The wrong refrigerant will certainly solve some issues, such as whether it will ever get fixed.
 
Real R12 is still available on eBay
https://www.ebay.com/itm/353555433403?hash=item52518bc7bb:g:G2IAAOSwhHRir1d4

s-l1600.jpg
 
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