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Discussion Starter #1
Hey all,


I've purchased an over the counter R134a A/C recharge kit.

I the can said to hold it with the nozzle down, So i drained 2 12oz can's with the nozzle down, both can's drained in about 30 seconds.

The system went from 0 PSI to 24PSI (Its suppose to be between 25-45 PSI)

Then, i bought a 3rd 12oz can, and i noticed it said hold the can nozzle UP...

So my first question is... did draining those 2 can's with the nozzle down, going to hurt anything?

and my second question is...

When i did try to drain the 3rd can with the nozzle up (I guess turning the liquid into gas), it took about 20-30 minutes to drain the can, where as when i held the can up side down, it only took about 30 seconds...

And when draining the can nozzle side up, it only went from 24PSI to 26 PSI....

Is that normal??
 

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Though I have done the same thing in the past draining with the nozzle down forces the gas into the line. They say that this can cause problems by over-pressurizing the system. You lucked out because your pressure was too low.

When you face the nozzle up the can equalizes with the pressure in the system. This is why the can did not increase the overall pressure of the system much past the factory design. Chances are you did not drain your can.

Bottom line, you are in good shape. Just don't do it again. :mad:

I would have put a little stop leak in there because your pressure was low. Next time?
 

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I think I may be low on refridgerant myself, cause when you turn on the AC the compressor kicks in for a second then turns back off, i've heard it does this when it is low. Now, I know there is some pressure inside the system still, should I just let it all out, and then refill it? Or just add to what is there?
 

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Discussion Starter #4
tommywdetroit said:
I think I may be low on refridgerant myself, cause when you turn on the AC the compressor kicks in for a second then turns back off, i've heard it does this when it is low. Now, I know there is some pressure inside the system still, should I just let it all out, and then refill it? Or just add to what is there?

Check the pressure with a guage...

You may have the same problem i just had.

The low pressure sensor switch may be going out.

What happened to me was, i would turn the A/C on, and it would get cold for 1 minute, then it would get warm, i looked under the hood and relyized that the compressor was stoping.

If you check your pressure, and its between 25-45PSI then your pressure is fine, and your low pressure sensor switch is probably bad... its like $18 from five start ford..

Here's a link to the part i'm talking about...

Ford A/C Diag
 

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ccornett said:



Check the pressure with a guage...

You may have the same problem i just had.

The low pressure sensor switch may be going out.

What happened to me was, i would turn the A/C on, and it would get cold for 1 minute, then it would get warm, i looked under the hood and relyized that the compressor was stoping.

If you check your pressure, and its between 25-45PSI then your pressure is fine, and your low pressure sensor switch is probably bad... its like $18 from five start ford..

Here's a link to the part i'm talking about...

Ford A/C Diag
Yeah.. i'll have to check that out, my friend had a gauge I can use, just have to wait for him to get off work. Thanks for the heads up too BTW.
 

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Here's the deal, seeing as how I'm an HVAC tech, when it comes to refridgerants I know a thing or two. R134a is a blended refridgerant, blended refridgerants ALWAYS are charged as a liquid, hence turning the can upsided down. Typically the longer the hose the better, but the low charge weight of an auto A/C systen hose length don't really matter, do yourself a favor and spend the $15 and buy a hose with an inline pressure gauge.
 

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When I recharged my system, I used a pressure gauge to monitor the high side.

When recharging with the refrigerant can upside down, fill the system slowly, and watch the pressure gauge. You fill it until the gauge indicates the recommended pressure, which is based on what the current outside air temperature is.

In my case, the recommended pressure was 175 psi
 

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For the everyday Joe they'll want to use the quick disconnect with the guage on the low side. Using the high side if you don't know what your doing it can be dangerous, it's easier to obtain your low side pressure, convert that to temperature and obtain your discharge temperature from one of vents inside the car. This will give your superheat value but that's getting too technical for someone not in the field, I know many auto mechanics that can't understand superheat and subcooling. Rule of thumb for the do it yourselfer, charge to approximately 30 psig on the low side, and that will put you right in the ballpark for a perfectly charged system. Hence the blue zone on the automotive pressure gauges. Going off your high side you do want to take ambient temps into consideration. You are 100% correct about not just opening up the valve all the way, you want to charge at about 10-15 psig over operating pressure. That's part of the reason I mentioned using a longer hose. Oh by the Rolling Thunder I want to thank you for pointing me in the direction of this board a few weeks ago on the other thunderbird forum. I have learned tons already.
 
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