Understanding the Auto-Defrost System in Refrigerators
Modern double-door and side-by-side refrigerators are marketed as "Frost-Free". They feature a built-in automated defrost cycle that turns on a small heating element every 8 to 12 hours to melt frost off evaporator coils. When this cycle fails, thick snow-like frost chokes airflow.
1. Defective Defrost Bi-Metal Thermostat
The defrost bi-metal thermostat senses coil temperature and cuts off the defrost heater once ice melts. If this switch fails, the heater never receives power, causing coils to freeze solid into a block of ice.
2. Malfunctioning Defrost Timer or Control PCB
The defrost timer governs when the compressor pauses and the heater turns on. A stuck timer keeps the fridge locked in permanent cooling mode, causing uncontrolled frost buildup.
3. Clogged Freezer Defrost Drain Hole
When the heater melts ice, the water drains through a small hole beneath the coil into an evaporation pan over the compressor. If dust or food crumbs plug this drain, meltwater refreezes on the freezer floor, forming an icy sheet.
4. Poor Door Gasket Seal
Continuous inflow of humid air through damaged rubber door seals causes rapid moisture condensation that overwhelms the capacity of the automatic defrost cycle.
Certified Refrigerator Defrost System Repair
Tru-FIX-IT technicians carry original defrost heaters, bi-metal sensors, and digital control boards for LG, Whirlpool, Samsung, and Haier refrigerators. Dial 9464881952 to book an inspection.