Defrost Heater Failure
The heater that melts coil frost stops working, so ice builds until airflow is blocked.
A defrost system that stops working does not announce itself — it frosts the coil quietly, then the fridge warms. Potomac Refrigerator Pros takes defrost calls by phone only, Monday to Sunday, 8:00 AM to 10:00 PM. Call (301) 368-8305 with the frost pattern, the fridge temperature, and the brand and model if known. A written estimate comes before work starts — no form, no email booking.
Serving Potomac, North Potomac and Montgomery County, MD, centered in Potomac Village, MD 20854
Name the exact symptom when you call, because a failed defrost cycle shows up in several ways: frost climbing the back wall of the freezer, a freezer that stays cold while the fridge section warms, water pooling under the crisper drawers, ice on food packaging, or a fridge that cools, then warms again between cycles. The defrost cycle normally melts frost off the evaporator coils every 8 to 12 hours; when the heater, bimetal thermostat, or control fails, ice builds behind the rear panel, airflow stops, and the fresh-food side climbs above 40°F. Potomac’s humid summers make this worse, because moist air entering through a weak seal adds frost faster than a healthy cycle can clear it.
No single symptom maps to one part. Diagnosis is inspection, with a multimeter and temperature readings, not a phone guess.
The heater that melts coil frost stops working, so ice builds until airflow is blocked.
The thermostat that ends the defrost cycle at the right temperature fails, and the cycle never runs properly.
The board or timer that starts the defrost cycle stops calling for it, so frost accumulates unchecked.
Even with a working heater, a dead fan cannot move cold air, so the fridge warms while the freezer stays cold.
Humid air entering through a torn gasket adds frost faster than the cycle can melt it.
Melt water has nowhere to go, so it pools under drawers or refreezes in the drain tube.
Food packed against vents starves the coil of air and mimics a defrost fault.
Check whether the door closes fully, look at the seal for tears or flattening, and check vents for blockage or overfilling. Take a thermometer reading from each section and write both down. Do not chip ice with sharp tools and do not use heat guns on the coil — practitioner guidance warns both can damage internal parts. Keep the door closed, move perishables to a cooler if the fridge section is above 40°F, and do not taste food to check it. Stop and call if water reaches electrics, you smell burning, or the breaker trips again. Never remove covers or touch refrigerant lines.
Call (301) 368-8305 with brand and model if known, the frost pattern, both temperatures, water under drawers, and whether the freezer section is still cold, and your area or ZIP code.
Diagnose on site: defrost heater, bimetal thermostat, control board or timer, evaporator fan, drain, airflow, and seals are tested. The failed part is named, not guessed.
Written estimate before work: plain-language diagnosis and estimate first, and you decide. If frost has damaged airflow for weeks, the replacement comparison comes before any work on an older unit.
Repair and test: The failed heater, thermostat, board, or fan is replaced, the drain is cleared, and both sections are rechecked for temperature. Temperatures are checked again — fridge at or below 40°F, freezer at 0°F — before the visit ends.
After: how to keep vents clear, check the seal, and watch for frost returning on the back wall. No fixed-for-life promise, and no term is stated that the partner has not confirmed.
No Potomac-specific repair price dataset exists, and none is invented here. Market figures, not a quote, and not a Potomac price. Your written estimate is the only price that counts.
$138–$350 typical, most around $220.
Source: Thumbtack refrigerator repair cost, 2026.
$200–$1,300, average $650, most $300–$1,000 — higher, likely including larger and sealed-system jobs.
Source: HomeAdvisor refrigerator repair cost, 2025.
| Part | National range |
|---|---|
| Defrost motor | $100–$440 |
| Control board | $80–$800 |
| Thermostat | $100–$440 |
If repair costs more than about half a comparable new unit, replacement is usually favoured; if far less, repair usually wins. Lifespans (Fridge.com analysis of DOE/AHAM data) are about 14 years for a top-freezer, 13 for a bottom-freezer, and 12 for side-by-side and French-door units, with built-ins about 15 years — guides, not promises.
Repair almost always.
Apply the 50% test: a fan, defrost part, thermostat, or seal is an easy yes, while a sealed-system repair near half the replacement price is not.
Apply the 50% test; minor fixes such as a seal, filter, valve, or thermostat can be worth it at any age.
With a major failure, replacement is usually favoured; sealed-system repair on a standard unit over 10 years old rarely pays.
The exception: a repair buying two or three more years on a perfectly fitting unit can beat a swap needing joinery, and replacement add-ons can add several hundred dollars.
For this fault specifically: a heater, thermostat, or drain repair on a fridge under 10 years old is usually an easy yes under the 50% rule, while a board repair on a standard unit over 10 years old deserves the replacement comparison first. A defrost fault caught early is a minor fix; left for weeks, the same fault can strain the compressor.
Call (301) 368-8305, Monday to Sunday, 8:00 AM to 10:00 PM. Serving Potomac, North Potomac and Montgomery County, MD, centered in Potomac Village, MD 20854. Outside this area, say your ZIP code on the call so range can be checked honestly.
Work is performed by a Maryland licensed holder.
Not sure you are in range? Call with your ZIP code — we are always happy to check.
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Montgomery County, MD
Straight answers for a fridge defrost fault in Potomac, MD — diagnosis first, written estimate before work.
Frost builds up when the automatic defrost cycle stops melting ice off the evaporator coil, usually because the defrost heater, bimetal thermostat, or control board has failed. Humid air entering through a weak door seal adds frost faster, so a seal leak and a defrost fault often appear together.
Detail: The defrost cycle normally runs every 8 to 12 hours. Diagnosis tests heater, thermostat, and board separately, because each failure looks the same from the outside — frost on the wall and a warming fridge section.
When frost locks the evaporator coil, cold air cannot move from the freezer to the fresh-food section, so the freezer stays cold while the fridge warms. The usual causes are a failed defrost heater, a failed bimetal thermostat, a control fault, or a dead evaporator fan.
Detail: Check vents for blockage and overfilling first, and listen for the fan. Do not chip ice with sharp tools. A technician tests fan, damper, and defrost parts, clears the frost lock, and confirms both sections reach temperature before leaving.
Manually defrosting can restore cooling for a few days, because it clears the frost lock, but it does not fix the failed heater, thermostat, or board that caused it. The frost returns, usually within a week or two, and the fridge warms again. Manual defrosting is a stopgap, not a repair.
Detail: If you defrost manually, keep the door closed afterwards, move perishables to a cooler while the fridge section is above 40°F, and do not use sharp tools or heat guns on the coil. The lasting fix is testing the defrost parts and replacing the one that failed.
Nationally, most fridge repairs fall in Thumbtack’s 2026 range of $138–$350, most around $220, while HomeAdvisor’s 2025 data runs $200–$1,300, average $650, most $300–$1,000. By part, HomeAdvisor lists defrost motors at $100–$440 and control boards at $80–$800. Neither figure is a Potomac price.
Detail: The spread exists because a heater or thermostat job and a board job are different repairs. A diagnosis and a written estimate before work are the only way to know where your repair falls, and that estimate is the only price that counts.
Left for weeks, a defrost fault does more than warm the fridge section: the compressor runs longer to compensate, food spoils early, water pools under drawers from a clogged drain, and the strained compressor can fail next. A minor part fault can therefore grow into a major repair if it is ignored.
Detail: Perishables above 40°F for over 2 hours (1 hour if above 90°F) should be discarded, per FoodSafety.gov guidance. Catching a defrost fault at the first frost on the back wall keeps the repair to the failed part, not the parts it strained.
A defrost fault usually shows frost on the back wall with a freezer that still feels cold, while a sealed-system fault usually shows little or no frost and both sections warming together, sometimes with clicking at startup. The two faults overlap, so the distinction needs inspection, not a phone guess.
Detail: Diagnosis tests defrost parts, fan, and damper first, then sealed-system pressures and temperatures. A written estimate comes before any work either way, and a sealed-system finding on an older unit brings the replacement comparison before approval.
Frost building up, or fridge warm while the freezer stays cold? Call (301) 368-8305 and tell us the brand, model, and symptoms. You get a written estimate before any work starts. No form, no email booking — phone only.
Call (301) 368-8305Service Area Map, centered on Potomac Village, MD 20854, as a geographic center only.