[ale] [WAY OT] WARNING - diy car ac recharge kits can be dangerous

[Ron Frazier (ALE)]

Hi all,

I just wanted to follow up and tell you how things worked out and share some more info.

I picked up the car and talked to the 2nd mechanic at the shop who is very familiar with ac systems.  He said:

* It is definitely possible to overcharge the system with those cans, and it's highly likely that is what I did.

* The little gauge on the can does little to tell you the state of your system.

* He sees this a good bit with other customers who've done the same thing.

* If you overcharge, the low side pressure can stay the same and the high side pressure will go up.  The gauge on the can only shows the low side pressure.

* The system has a high pressure cutout switch that is supposed to prevent failure.  The switch is always on under normal circumstances to allow the compressor to run.  In my case, the high pressure cutout switch did its job.  But, the switch can fail on, in which case, excessive pressure can develop.

* He has seen a case where someone overcharged a system and where the high pressure cutout switch had failed on.  The compressor exploded.  Fortunately, then mechanic had not yet opened the hood and got close to the compressor when it went.  He said the result was NOT pretty.

(Ron talking again.)

My opinion, for what it's worth, is that it's unlikely that the high pressure cutout will fail.  But, obviously, it can happen.  That, combined with erroneous maintenance, can be catastrophic.

The mechanic checked my wife's car (for free) and the pressures in it's system are fine.  In her car's particular case, it's about 30 PSI on the the low side and about 150 PSI on the high side.

So, that totally settles it.  I will NOT be using the DIY  ac recharge cans again.

My little lesson in air conditioning physics (and marketing) only cost me $ 102.  I'm glad it wasn't lots more.

Sincerely,

Ron



"Ron Frazier (ALE)" <atllinuxenthinfo at techstarship.com> wrote:

>Hi Dustin,
>
>You're welcome.  Don't scare him half to death.  If the compressor is 
>running, it at least means the sensors are happy.  If it's cutting out 
>frequently, that doesn't necessarily mean it's low on refrigerant.  In 
>that case, it could be overcharged.  It might be a good idea to have a 
>pressure test done by a reputable mechanic though.  Good luck.
>
>It just so happens that my mechanic called me while I was typing this 
>reply.  I got out light.  It's possible that there was some blockage in
>
>the system and it's possible that I overcharged it.  He couldn't tell 
>for sure what was the cause of the problem.  All we know is that after 
>he evacuated the system completely (using a vacuum device) and
>recharged 
>it properly, it's working again.  Cost was $ 102.
>
>Yea!  $ 100 is better than $ 500 is better than $ 1000.  Considering
>the 
>potential problems, I doubt I'll be using the cans any more.
>
>Gonna have the wife's car checked for pressure just to be sure 
>everything is safe.
>
>Sincerely,
>
>Ron
>
>
>On 8/15/2013 2:48 PM, Dustin Strickland wrote:
>> Thanks for the tip - my grandfather has been religiously using those 
>> cans over the summer for about 3 years, though so far he has suffered
>
>> no ill-effects. I'll pass it on to him that he should get it checked 
>> so that his hood doesn't explode off the front of the car when he's 
>> sitting at a red light on a hot day
>>
>>
>> On Thu, Aug 15, 2013 at 2:40 PM, Ron Frazier (ALE) 
>> <atllinuxenthinfo at techstarship.com 
>> <mailto:atllinuxenthinfo at techstarship.com>> wrote:
>>
>>     Hi all,
>>
>>     OK, yes, definitely not Linux related, but I thought you guys
>>     might want to know this and, well, I'm not active on car forums.
>>
>>     I've learned the hard way that diy ac recharge kits can be
>>     dangerous.  How hard the hard way is has yet to be determined.
>>
>>     So, I traded one car and got another used car last year.  The ac
>>     seemed to be running intermittently, so I get the handy r134
>>     recharge kit from autozone with the built in low pressure gauge
>so
>>     you can tell what you're doing.
>>
>>     Instructions say, basically, adjust the pointer on the gauge for
>>     the outside temperature, connect hose to low side ac port, run
>>     compressor, squeeze trigger and periodically shake the can.  You
>>     should be done when gauge is in green zone and air is cold.  So,
>I
>>     watch the gauge and keep squeezing the trigger.  It never leaves
>>     the green zone.  I keep doing this for a while ASSUMING the magic
>>     gauge will let me know if there is a problem.  After a while,
>>     things are stable and the gauge is not varying much.  Air is
>cold,
>>     so I disconnect everything and go do the same procedure on my
>>     wife's car.
>>
>>     Note, the instructions say DO NOT OVERCHARGE!, but the clear
>>     implication is that you're not overcharging as long as the gauge
>>     is in the green.
>>
>>     Fast forward to a couple of days ago, my ac is again intermittent
>>     on a hot day, so I repeat the procedure.  Same results on the
>>     gauge.  But, not the same results under the hood.  Now the
>>     compressor literally runs only for 1 second or so.  A couple of
>>     times, when it tries to turn on, I hear this grinding noise and
>>     see smoke.  Pretty sure that was the clutch slipping.  I turn the
>>     unit off and take it to my mechanic.
>>
>>     He calls me later and tells me my high side pressure (which is
>not
>>     measured by the diy kit) is around 400 PSI and he's surprised
>that
>>     the whole system hasn't exploded.  Wow, that was fun to hear.
>>      He's going to evacuate and recharge the system and we'll find
>out
>>     if anything has been damaged.
>>
>>     So, APPARENTLY YOU CAN OVERCHARGE with a diy kit and you'll never
>>     know it.
>>
>>     Try googling diy ac recharge overcharge, and you'll get some
>>     interesting results.  One forum post says you can only know if
>>     you've charged enough by weight, not by pressure.
>>
>>     So, now I have to pay $ 100 to evacuate and recharge my car ac.
>>      Then, I have to do the same to my wife's car, because I don't
>>     know if it's safe or not.  Then, if I've damaged something, I
>have
>>     to figure out whether I want to pay hundreds more dollars to have
>>     a working ac again or just sweat it out.  I'm really hoping the
>>     system will still work.
>>
>>     If it's that easy to screw the system up and it's that hard to
>>     tell if you're doing it right, I almost think these products
>>     shouldn't be on the market.
>>
>>     Hard lesson learned.  It could have been a lot harder.  I guess I
>>     could have caused an explosion.  Hopefully, the high pressure
>>     sensor would have just disabled the system before that.
>>
>>     If I have to replace the compressor, drier, and expansion device
>>     (usually done together), this looks like a good source online.
>>      I've never used them, just read the website, but they have a
>>     complete kit for my car for $ 300.
>>
>>     http://www.discountacparts.com
>>
>>     Like I said, just passing this along.  Maybe my story will save
>>     someone else some grief.
>>
>>     Sincerely,
>>
>>     Ron
>>




--

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Ron Frazier
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