Ninja tips: AC systems |
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Ninja tips: AC systems |
technicalninja |
Mar 24 2023, 07:32 AM
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#1
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Senior Member Group: Members Posts: 1,342 Joined: 31-January 23 From: Granbury Texas Member No.: 27,135 Region Association: Southwest Region |
This thread is my base AC thread for suggestions, questions, whatever...
I run https://granburyautoac.com/ I specialize in automotive heat and air conditioning systems. I've been doing AC work since 1983 and have seen all of the changes, good and bad, that have occurred over the last 40 years. I'm keeping the first post short as they always show up at the top of each page and if long, they clutter up the thread... |
technicalninja |
Mar 24 2023, 09:40 AM
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#2
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Senior Member Group: Members Posts: 1,342 Joined: 31-January 23 From: Granbury Texas Member No.: 27,135 Region Association: Southwest Region |
The very first thing I do when checking a system out is feel the aluminum tubing by hand to see if I have any heat transfer going on.
The high side discharge hose from the compressor to the condenser is the very hottest hose in the system. On a 80 degree day it should be warm-hot, on a 100degree day it will be hot, hot like a cloths iron. Be careful here; this line has the ability to burn you. The liquid line from condenser to expansion device will still be warm but much cooler than the discharge line. Barely warm on a 80 degree day, warm-hot on a 100 degree day but you should be able to hold on to it without burning your hand. The low side hose from the evaporator to the compressor (suction line) should be cold/cold. When working properly it will be similar to grabbing on to an ice cube. This cold starts from the evaporator and extends down to the compressor. A slightly low system will have this line getting warmer that closer to the compressor it gets. We want the liquid refrigerant finishing its phase change at the entrance to the compressor. The phase change absorbs as much as 100 degrees of temperature and a cold line all the way to the compressor is what we are looking for with one exception. Late modern systems use a secondary cooler where the liquid line post condenser gets wrapped around the suction line to absorb the extra cooling that is available in the suction line. Suction line post secondary cooler is not cold like the entrance suction to the secondary cooler. This secondary cooler is old school technology. Mercedes used this set up in the late 70s to cool the return fuel to the fuel tank to reduce evapoatory emissions. What was once used to cool fuel is now used to cool refrigerant. These secondary coolers are far more common on R1234yf systems but some late R134a systems have them. @ClayPerrine This is a item I may try to incorporate into a modern 914 system to do what you have done by adding a secondary condenser. I just need to find a secondary cooler that is long and thin to work in the right side rocker panel where the lines go in a stock ac equipped 914. This is it for my text barfing for today. I've got to go fix a bunch of ac systems and will be busy... |
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