During this visit I discovered that compressor #1 was not operating due to a low pressure safety switch (18psi). I checked the schrader valves and braze joints outside. The inside braze joints, capillary tubes and the coil elbows that were accessible were checked. I did find that the evap coil is leaking refrigerant. A video was taken and is in service titan. Tech notes: ahu m/n TAA240S4D-1Y s/n 5616B05048 age (7yrs). Lennox Condenser m/n TSA240S4, s/n 5616A10167 age (7yrs) Lennox **** while the ahu is from 2016, there is history of this exact problem occurring in 2020. ****