UV Dye Sealant & R-22 Refrigerant Charge

Customer's attic system wasn't cooling as well as it once did. With high 90 degree temperature days the thermostat struggled to bring down the temperature to their desired set point temperature. Upon gauging up found out that system was low on cooling. Provided them the option to add a UV Dye Sealant and charge up R-22 refrigerant to bring temperature difference to expected range. Customer agreed and I proceeded to conduct agreed upon services.
Returned after 21-days and found the UV Dye Sealant inside the indoor coil with the aid of a UV Flash light. Checked temperature difference across coil and found that it had maintained itself since my last visit. This is a successful intervention which allows the customer to gain the most benefit from an older R-22 based system.