What is the first thing a technician should know?
Before beginning troubleshooting a technician should know how the equipment is suppose to be functioning: (how it suppose to sound, where it suppose to be cool or hot, when a particular fan it supposed to operating) also the correct operating pressures for typical system.
What causes high suction pressure on AC unit?
The results are high suction pressures. A leaky discharge valve will also allow discharge gas to sneak into the compressor’s cylinder during the down stroke of the compressor. This will cause the suction pressure to increase because of the suction valve being open during part of the down stroke of the compressor.
What happens if suction line is too big?
Among other things, an incorrectly sized line set can lead to premature compressor failures. When determining the size of suction lines, the line must be kept large enough to minimize pressure drop, which minimizes capacity loss, but small enough to keep velocities high enough to maintain oil return to the compressor.
How much freon do I put in a line set?
Now you need to know that pipe size so let’s say 1-1/8″ suction line and a 5/8″ liquid line (commercial unit). Then take the 69.92 and divide that by 16 ounces per pound and you need to weigh in 4.37 pounds (or 4 # 5.92 ounces) of additional refrigerant to complete the system charge.
How do I calculate how much refrigerant I need?
Divide this amount of heat by the refrigerant’s heat transfer rate. If the refrigerant moves, for instance, 170 kj/kg, then: 263,750 / 170 = 1,551 kg. Multiply this weight by 2.2 to convert it to pounds: 1,551 x 2.2 = 3,412 lb.
How do I calculate how much Freon I need?
Estimating Charge Needed for Refrigerant Lines Note that the amount of charge will be very different for the liquid and suction lines, and they should be added together to find the total weight per foot. Finally, multiply the length of the lines in feet by the weight per foot to find the total charge needed.
How much refrigerant should I add?
Most newer passenger car A/C systems do not hold much refrigerant (only 14 to 28 oz.), so you don’t want to add too much if the system is low. One can of R-134a typically holds 12 oz. of refrigerant.
What happens if I put too much refrigerant in my car?
If it’s overcharged, the decompression from liquid into gas can’t occur so your compressor is squirting out liquid coolant instead of gas coolant. The results will be a noticeable sound as your AC compressor struggles to pump everything through the lines.
How many cans of AC recharge do I need?
anyways fyi: you can put 2-3 cans you need to put the exact amount or it won’t cool right. the only way to do it vaccum the system leak test etc might as well do everything. I don’t think you’ll get 3 pounds in there. Pressures are going to equalize to what the cans have in them and you won’t get any more in.
How many cans of freon is 3 pounds?
4 cans
Do you fill AC on the high or low side?
The high side fitting is located between the AC compressor and condenser and is the larger of the two fittings. Consult the service manual to verify the exact location of the low-side service port. If hooking a can of refrigerant with a single hose/gauge to the car, you will use the low side.
What is the correct AC pressure?
The low-side should be near 30 PSI at 90 degrees Fahrenheit or less. Pressure that is too much lower or higher shows there is a problem. On a properly working system, high-side pressure will be about twice the ambient temperature, plus 50 PSI.
How long should AC vacuum hold?
5-45 minutes