There are many ways you can spot a refrigerant leak, I will begin with the easiest and most common.
1. There will be oil around the leak, the more oil the bigger the leak... a very slow leak will have dust accumulating on the oil. A large leak will have a drop of oil hanging under the leak if its on pipe.... this is because a bit of oil travels with the refrigerant.
2. Use a 'halide torch' this works will all refrigerants that have a chlorine atom in the molecule. You can buy a halide torch on line or at Grainger Industrial supply or Johnstone supply for less than $30
3. Use a liquid soap bubble type leak detection solution, most auto supply stores carry them, and so do the above mentioned stores. $3.00 with a dobber in the bottle. any leak creates bubbles.
Here is a range of more exotic leak detection tactics most more expensive, there are dyes that
you can inject to a system, and then if there is a leak, you can spot them easily with an ultra violet light.
We can go from there without a time limit as needed.
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