{ "item_title" : "HVAC Service Procedures and Refrigerant Charging Explained", "item_author" : [" Jonathan R. Clifford "], "item_description" : "The system that cooled fine last spring is low on charge again - and until you find the leak, fix it, pressure test it, and evacuate it correctly, everything else is just adding refrigerant to a problem.Most callbacks happen because the diagnosis stopped at the gauges. High superheat gets refrigerant added. Low subcooling gets refrigerant added. A restricted filter-drier, a dirty condenser coil, and a failing compressor all get refrigerant added - until the compressor burns out and the customer stops calling you back for good.This book builds the diagnostic foundation that stops that cycle: the refrigeration principles, the pressure-temperature logic, the charging methods, and the electrical troubleshooting skills that let you read a system correctly the first time and fix the actual problem.Inside, you will find:- The vapor compression cycle explained in field terms - not theory for theory's sake, but the pressure-temperature relationships you use every time you connect a manifold- Four pressure relationship patterns that identify the fault category before you touch a single component- The superheat and subcooling charging methods applied correctly - including why the metering device type determines which method you use and what happens when you use the wrong one- EPA Section 608 recovery, evacuation, and documentation requirements explained with the field procedures that keep you compliant on every service call- Leak detection using electronic, UV dye, and ultrasonic methods - combined with nitrogen pressure testing and micron gauge decay testing- Heat pump reversing valve diagnosis, defrost system verification, and mode-specific charging in both cooling and heating operation- Mini-split and VRF commissioning, factory charge correction, error code interpretation, and inverter compressor service- Electrical troubleshooting using voltage drop testing, capacitor microfarad measurement, contactor diagnosis, and control board input-output signal verificationThis book is written for HVAC apprentices, entry-level service technicians, EPA 608 candidates, NATE examination candidates, and field technicians building the diagnostic skills that separate them from parts changers.GRAB YOUR COPY NOW", "item_img_path" : "https://covers3.booksamillion.com/covers/bam/9/79/819/580/9798195806354_b.jpg", "price_data" : { "retail_price" : "80.99", "online_price" : "80.99", "our_price" : "80.99", "club_price" : "80.99", "savings_pct" : "0", "savings_amt" : "0.00", "club_savings_pct" : "0", "club_savings_amt" : "0.00", "discount_pct" : "10", "store_price" : "" } }

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