Temperature sensor
Common error-code part. Confirm resistance and connector style.
Heatcraft Walk-In Cooler Error Codes — What They Mean
Heatcraft Refrigeration Products (brands: Bohn, Larkin, Climate Control, Inter-City) makes evaporator coils and unit coolers for walk-in coolers and freezers across food retail and foodservice. Heatcraft unit coolers with electronic controls (EC controllers) display alarm codes when faults are detected.
| Alarm | Meaning | Urgency |
|---|---|---|
| 1 | High temperature alarm | High |
| 2 | High discharge temperature | High |
| 3 | Low suction pressure | Medium |
| 4 | High suction pressure | Medium |
| 5 | Defrost termination fault | Medium |
| 6 | Evaporator fan motor fault | High |
| 7 | Temperature sensor fault | Medium |
Most Common Heatcraft Walk-In Alarms and Fixes
Alarm 1 — High Temperature
Box temperature exceeded setpoint. Immediate action required if product is at risk. Check: evaporator fan motors running, coil not iced over, condensing unit operating, door seals intact.
Alarm 2 — High Discharge Temperature
Discharge line temperature too high. Most common causes: dirty condenser on condensing unit, condenser fan failure, refrigerant overcharge, restricted liquid line.
Alarm 3 — Low Suction Pressure
Low refrigerant charge is most common. Also check: dirty evaporator coil (restricted airflow), TXV malfunction (sticking closed), or liquid line filter-drier restriction.
Alarm 5 — Defrost Termination Fault
Defrost failed to terminate properly. Check defrost termination thermostat and heater continuity. On air defrost systems, check fan operation and ambient conditions.
Alarm 6 — Fan Motor Fault
Evaporator fan motor failure or overload. Check motor for seized bearings and correct rotation direction.
Alarm 7 — Temperature Sensor Fault
Air temperature sensor open or shorted. Test sensor resistance and replace if out of spec.
Parts Often Needed
| Part | Notes |
|---|---|
| Evaporator fan motor | Match to Heatcraft unit cooler model |
| Air temperature sensor | Replace if resistance out of spec |
| Defrost heater | Replace if open circuit |
| Defrost termination thermostat | Replace if open at room temp |
Need Replacement Parts?
Before ordering, match the refrigeration part to the model number, electrical rating, and failure symptom. Check current prices on Amazon - prices and availability change frequently.
When to Call a Pro
Alarms 3 and 4 (pressure faults) indicate refrigerant circuit issues requiring an EPA 608-certified technician. All refrigerant work requires proper recovery and certification.