Springtime HVAC Maintenance for a commercial client near Heritage Ave. Performed a three system maintenance on RTU’s. Checked all electrical, mechanical and safety components, checked capacitors and amp draws, changed filters and cleared drain lines. Found on RTU 1&3 circuit 1 is low on Freon somewhere around 2-3 pounds. Put estimate together to either do leak search for add refrigerant. Everything else is Operating properly at this time.