air conditioning

Don't claim to be an "expert", but am trained and certified in mobile and stationary refrigeration... what's the issue?
 
first , are you hooking high and low up and getting a reading, 40 lbs is a about normal for the low side when ac unit is running, high side should run about 225 to 290, depends on the temp that day and humidity, I would hook both gauges up and add one can of freon,turn the ac on while adding freon and see if the compressor kicks in, one good rule of thumb that was giving the other day was to feel the lines on the low side around and the dryer, if its good and cold you sould be good
 
ok ran psi up to 60 and still nothing so hooked my power probe up to the compressor gotta good ground so i hooked probe to the other wire and gave er 12 volts and it still wont kick on so i think my clutch is Bad
 
Look on the gauges. They are calibrated in temperature and pressure. The difference between ambient and the condenser is + 30 degrees on the condenser output and on the evaporator and ambient (house, cab, car, truck interior) is -30 when she is running right. If the system is off and you hook in your gauges, if they don't record ambient as high as it is, you are low for sure. When fired up, temp varies all over the place and really is not a good measure of whether or not your system is full. Reason is external air across the coil and condition of it.

Gotta use the right freon. Gotta be careful putting it in to not over load it and not let any air or moisture in. Best to bleed the hose before connecting......bleed by punching the can with the valves off, catch a couple of threads on the connector and crack the can valve so that a little is spewing out while you tighten the hose down to the system.

If you are charging at the accumulator, you can invert the can and introduce liquid...goes faster that way. If you are in the line to the suction port of the compressor on a mobile system, keep the can upright and let the gas only out. This takes a long time and you usually have to sit the can in a pot of hot water to get the vapor pressure up high enough to get it all out but if you put liquid right in the compressor intake you can blow your reeds....Heat, AC, and refrigeration 101. On mobile units, if you run your water hose on the condenser coil (the one in front of the radiator) it will cool the freon, reduce the temperature, which will reduce the system pressure thus helping you get all the freon out of the can. Back to my pressure not good comment above, when you hit the coil with water, both pressures nose dive and you can't make any educated decision from anything like that.

Best way to tell if you are full is to check the sight glass on top of your dryer canister if it has one or wait till early in the morning when everything is cool. The sight glass is clear on two occasions: engine not running or out of freon, or full. Anywhere in between you will have bubbles which diminish in quantity as you near full. Fire up the rig and put the blower on normal, windows closed with rpms at least 1500 or so. Give her 4 or 5 minutes. If you get sweating on the suction line (the big line on the compressor) all the way back to the compressor you are good to go.

Quick tutorial but they make books with the whole story.

Good luck,
Mark
 
very good information thanks . i tried sending power to the clutch on my other truck that the ac works on and the clutch will snap reward towards the compressor . i cannot get the clutch to move on the dodge now matter what i do as far as powering the clutch wires
 
There's a magnetic clutch on the compressor pulley that closes when 12 v is applied to connect the pulley to the shaft of the compressor and run it. Pull the connector off the clutch and measure the resistance between the terminal and the case (no paint) of the compressor. With an assumed couple of amps to pull it in, resistance should be single digit ohms. If open circuited, or high resistance, clutch coil is bad.
 

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