Thermistor
Common temperature-sensing fault part. Confirm resistance range and connector.
Larkin Refrigeration Error Codes — What They Mean
Larkin is a Heatcraft Refrigeration Products brand used in walk-in coolers and freezers across grocery, foodservice, and cold storage. Like Bohn and other Heatcraft brands, Larkin unit coolers share the same EC controller platform with identical alarm codes.
| 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 Larkin Alarms and Fixes
Alarm 1 — High Temperature
Product at risk. Check: all evaporator fans running, coil not heavily frosted, condensing unit operating correctly, walk-in door seals intact.
Alarm 3 / 4 — Pressure Alarms
Alarm 3 (low pressure) most often indicates low refrigerant charge or a TXV stuck closed. Alarm 4 (high pressure) most often indicates a dirty condenser or failed condenser fan. Both require certified refrigeration service.
Alarm 5 — Defrost Fault
Defrost ran past the expected termination point. On electric defrost, check heater continuity and termination thermostat. On air defrost walk-ins, check that fans are operating correctly and drain is clear.
Alarm 6 — Fan Motor
Motor overload or failure. Check for seized bearings and run capacitor failure.
Alarm 7 — Sensor
Replace NTC air temperature sensor if resistance is out of spec (open or near-zero).
Parts Often Needed
| Part | Notes |
|---|---|
| Evaporator fan motor | Match to Larkin unit cooler model and voltage |
| NTC temperature sensor | Larkin/Heatcraft part |
| Defrost heater | Match wattage and voltage |
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
Pressure alarms (3 and 4) require EPA 608 certified technician for refrigerant diagnosis and repair.