Author Topic: another AC question  (Read 1218 times)


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another AC question
« on: April 15, 2009, 08:36:41 PM »
Hi all
I am here at the knowledge pool again for a drink. I listened to your suggestion of going to Johnstone supply but thought I'd be smarter and go to my local Naughtons. I called them and asked if they had a drier with pipe threads or flare fittings and they said yes, so I drove twenty plus miles only to find they were full of you know what. All they had were sweat on driers. So I got to looking at the Johnstone catalog and they have what I need but I noticed an arrow for direction of flow on the driers. Which way does the liquid flow in the vapor cycle world. The liquid line is the small 1/4" line and does it flow toward or away from the compressor? I have not a clue.

Offline Don4107

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Re: another AC question
« Reply #1 on: April 15, 2009, 11:12:50 PM »
The flow is from the compressor high side via the smaller/liquid line to the condenser.  Then to the evaporator and then typically a larger/vapor line to the accumulator/dryer that feeds the low side (suction) side of the compressor.

Fire up your car and turn on the AC.  The high side/smaller line will be warm/hot.  Trace the lines and you will get a better understanding of the flow of things.

Putting together an AC system requires that everything in the system is sized properly to run efficiently.  The charge has to be right including the amount of oil in the system if it is to live for long.  The condenser has to have enough air flow to work properly.  If you want to see what difference condenser air flow can make to head pressure, put your gauges on a rig and take static reading setting still and then again driving down the road.  HUGE difference.

One of the biggest variables in getting the charge/oil right in a nonstandard system is accounting for longer than normal lines.  Sometimes the only way to do it is experience with the type of system and refrigerant under the existing conditions.

Good luck
Don 4107
Don 4107 Eastern Washington
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Offline Nick Badame Refrig/ACC

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Re: another AC question
« Reply #2 on: April 16, 2009, 03:57:32 AM »
Hi Rick,

As easy as I can explain.....  From the outside unit, point the arrow on the dryer twards the inside evaporator.

There may be an accumulater inbetween, if so, after the accumulater.

Whatever it takes!-GITIT DONE! 
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Offline RichardEntrekin

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Re: another AC question
« Reply #3 on: April 16, 2009, 05:49:37 AM »
You might want to spend some time polking around to understand A/C basic theory before you gas up your rig. About 10 gazillion google hits, you choose.

Here is a site that has some helpful info. It's not gospel, but it's helpful for determining ballpark charge amounts and oil amounts.
Richard Entrekin
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Inverness, Fl

Often wrong, but seldom in doubt