Notice: We maintain high standards of excellenceand strive for 100% customer satisfaction! Please don't open cases or return requests without contacting us. If you have any questions about quality, shipping or other problems, please contact me first via eBay message I will give you a satisfy solution. 1. Before installation, be sure to repeatedly clean the air conditioning system to remove the pipeline and fill the pipeline with cleaning agent. Condenser, evaporator soak for about 20 minutes until the cleaning agent out of the cleaning is clear. 2. replace the drying bottle 3. Be sure to clean the expansion valve (or replace with a new one) .