Checking to see if you have a refrigerant leak
Recently I visited a customer who was selling her home and she had a situation where the air conditioner not cooling to the set temperature at which she had it set. She had called another HVAC repair company who came out and added R22 and cleaned the condenser coil. One week later the air conditioner was not cooling again so she called us.
Most of the time when we get a call for ac not cooling, we see that the evaporator coil has a leak. So my first step was to take an electronic refrigerant detector up to the attic and check the evaporator coil for leaks. I did not find any sign of a leak while I was there. Then I went outside and connected my manifold gauges and did find the system slightly under charged.
Since it was low, I checked the receipt from the previous service to see how much refrigerant was added. It appeared to be a minor leak so I took out the electronic refrigerant detector once again. This time I checked the condenser coil and I was getting several hits. So I began to look for visible signs of a leak, checking for oily residue on the line set and the internal lines. I didn’t find any evidence on the outside of a leak so I removed the fan cover and inspected the inside of the coil. And the image on the right shows two locations where the oil residue was plainly visible on the coils. And yes even Trane air conditioners have leak issues.
