Hotpoint Refrigerator dH: Defrost Heater Circuit Open

Why dH Gets Worse Every Day

Your Hotpoint refrigerator displays dH — the defrost heater circuit is open, meaning the heater cannot activate during the automatic defrost cycle. This may not feel urgent because the refrigerator is probably still cold right now. But dH is a progressive failure: without working defrost, frost accumulates on the evaporator coils behind the freezer panel. Each day, the frost layer grows thicker, blocking more airflow across the coils. Over 1-3 weeks, the frost becomes a solid ice sheet that completely blocks air circulation, and the refrigerator and freezer stop cooling.

Timeline without repair: Day 1-3: normal cooling, code displayed. Day 4-10: freezer temperatures begin rising, ice cream softens. Day 10-20: freezer above 10 degrees F, refrigerator compartment above 42 degrees F. Day 20+: food safety compromised, both compartments above safe temperature.

Act on dH sooner rather than later to avoid food loss and the need for emergency manual defrost.

The Automatic Defrost System

Every 8-12 hours (model-dependent), the refrigerator enters a defrost cycle:

1. The compressor shuts off
2. The defrost heater activates — a resistive heating element (calrod or glass-tube type) mounted directly on or adjacent to the evaporator coils
3. The heater runs for 15-30 minutes, melting accumulated frost from the coils
4. Meltwater drains through a channel into a pan beneath the refrigerator, where it evaporates from compressor heat
5. The defrost termination thermostat monitors evaporator temperature and cuts the heater when coils reach approximately 45-55 degrees F
6. The compressor restarts and normal cooling resumes

dH posts when the board attempts to activate the defrost heater and detects an open circuit — no current flows through the heater.

Defrost Heater Failure

The most common dH cause is a broken defrost heater element. The heater is a resistive wire inside a metal (calrod) or glass tube, mounted on the evaporator in the freezer compartment behind the rear panel.

Testing: Disconnect power. Remove the freezer rear panel (inside the freezer — typically 4-6 screws holding a plastic or metal cover). Behind this panel is the evaporator coil assembly with the heater element attached. Disconnect the heater's wires and measure resistance across the terminals: expect 20-80 ohms. Open circuit (infinite resistance) = heater is burned out.

Heater replacement: $25-$55. The heater clips or slides into brackets on the evaporator frame. On Hotpoint refrigerators, this is a straightforward swap once you access the evaporator compartment.

Defrost Termination Thermostat

The defrost termination thermostat (also called the bi-metal thermostat) is in series with the defrost heater — it cuts power to the heater once the evaporator reaches a safe temperature, preventing the heater from running indefinitely and overheating the compartment.

If this thermostat opens permanently (fails in the open position), it breaks the heater circuit regardless of heater condition. The board sees the same open-circuit signature as a dead heater and posts dH.

Testing: The thermostat is clamped to the evaporator tubing. Disconnect its wires and test for continuity at room temperature (below the thermostat's opening temperature). It should show continuity (closed). If it reads open at room temperature, it has failed.

Thermostat replacement: $10-$25. Often sold in a kit with the heater since both are commonly replaced together.

Wiring and Connectors

The defrost heater circuit runs from the main board to the thermostat and heater, passing through the freezer compartment. Wires in this circuit are exposed to freezing temperatures and moisture (condensation that refreezes). Over years, wire insulation becomes brittle and copper conductors break — especially at connector pins and at points where the harness passes through the foam insulation of the freezer walls.

Inspect all connections in the defrost circuit for corroded pins, frost accumulation on connectors, and broken wires. A broken wire anywhere in the circuit creates the same dH condition as a dead heater.

Manual Defrost Before Repair

If significant ice has already accumulated on the evaporator by the time you address dH, you will need to defrost manually before the repair can improve cooling:

1. Remove all food from the freezer and refrigerator
2. Unplug the refrigerator
3. Open both doors and place towels around the base to catch meltwater
4. Wait 4-8 hours for the ice to melt naturally, OR use a hairdryer on low heat directed at the evaporator (keep the dryer 6+ inches from the coils to avoid damaging plastic components)
5. Once all ice is melted, mop up the water, complete the heater/thermostat repair, and restore power

Do NOT use sharp tools to chip ice from the evaporator — puncturing a coil causes a refrigerant leak that destroys the sealed system.

Cost Summary

Hotpoint Evaporator Access

Hotpoint refrigerators have a relatively straightforward evaporator access path. Remove the freezer rear panel (typically secured by 4-6 Phillips screws), and the evaporator coil assembly with heater and thermostat is directly visible. On premium GE models (Profile, Cafe), additional panels, icemaker assemblies, and fan shrouds may need removal first. Hotpoint's simpler construction reduces the labor time for dH repair.

Questions About Hotpoint dH

My Hotpoint refrigerator still seems cold with dH showing. Do I need to act now? Yes. The refrigerator is cold because frost has not yet blocked the evaporator coils enough to impair cooling. But frost accumulates daily without defrost. Within 1-3 weeks, cooling will fail. Acting now prevents food loss and avoids the need for emergency manual defrost.

How do I know if the evaporator is already iced over? Remove the freezer rear panel and look. If you see thick frost or a solid ice sheet covering the coils, manual defrost is needed before or during the repair. A thin frost layer is normal during the period between defrost cycles.

Can I just manually defrost every few days instead of repairing dH? Technically, yes — but this requires removing all food, unplugging for 4-8 hours, and repeating every 3-7 days. The defrost heater repair costs $150-$260 once and permanently restores automatic defrost. Manual defrost every few days is impractical and risks food spoilage each time.

dH on your Hotpoint refrigerator? We carry heaters and thermostats for immediate repair — preventing the ice buildup that eventually causes cooling failure. Book your repair.