Which Heatcraft controller is on your Bohn or Larkin walk-in — and what do its codes mean?

Heatcraft Refrigeration is the biggest name in walk-in cooler and freezer refrigeration in North America — its equipment sells under the Bohn and Larkin brands (plus Climate Control and Chandler), so if your walk-in's evaporator says Bohn or Larkin on it, Heatcraft's controllers are what's talking to you. Current unit coolers ship with the intelliGen controller: an OLED display with a colored light bar where red plus an AL code is an alarm (AL01 high box temperature, AL06 door open), yellow plus an ER code is an error — usually a failed sensor — and IN codes are informational. Units running the newer A2L refrigerants add leak-detection alarms (AL12, ER32) that are evacuate-ventilate-and-call events, not troubleshooting exercises.

The previous generation, Beacon II, uses A1–A4 alarms and E1–E9 errors, several of which pump the system down and keep it off until the failed sensor is replaced — which makes an E-code on a Beacon II an urgent call, because your product is warming while it waits. Find your exact code below for the documented meaning, the checks facility staff can safely make, and the point where the clock says call now.

Which Heatcraft (Bohn/Larkin) controller do you have?

Heatcraft intelliGen

The intelliGen refrigeration controller is Heatcraft's current-generation control system, factory-fitted to unit coolers sold under Heatcraft's brands — Bohn and Larkin most commonly, along with Climate Control and Chandler. If your walk-in's evaporator carries one of those nameplates and shows a small OLED text display with a colored light bar, this is your controller. It reports with AL (alarm), ER (error), and IN (information) codes on the display, backed by the light bar: green is normal, yellow is a non-critical fault, red means act now. On newer A2L-refrigerant unit coolers it also runs the built-in refrigerant leak detection system. Practical tip: photograph the display before power-cycling — the code and light bar color together tell the technician most of the story.

All 37 Heatcraft intelliGen codes — meanings, checks, diagnosis and parts →

Heatcraft Beacon II

Beacon II is Heatcraft's previous-generation smart refrigeration system, shipped for years on walk-in evaporators and condensing units branded Bohn and Larkin (plus Climate Control and Chandler). Huge numbers of these are still running in restaurants and stores, so these codes come up constantly on older boxes. The evaporator control board reports through a simple two-digit readout: A-codes (A1–A4) are alarms about box conditions, E-codes (E1–E9) are equipment faults like failed sensors or tripped compressor safeties. On multi-evaporator installs, which board shows the code tells you where the problem is. Practical tip: write down the exact code and whether the compressor is running before resetting anything — several Beacon II faults pump the system down and keep it off until repaired.

The Beacon II Smart Controller is the optional wall-mounted LCD display that ties into Beacon II evaporator boards on Bohn and Larkin walk-in systems, letting staff monitor several coolers and freezers from one panel outside the box. Instead of two-digit codes it shows scrolling text messages — like *BOXHI or *INFLT with "CALL FOR SERVICE" — plus the system number affected, and sounds a buzzer. Remember it is a messenger: the fault it reports lives at the evaporator board or refrigeration system it monitors, not in the display itself. Practical tip: press CLEAR to silence the buzzer, but write down the message and system number first — that pairing tells the technician exactly which unit to walk to.

All 20 Heatcraft Beacon II codes — meanings, checks, diagnosis and parts →

Every Heatcraft (Bohn/Larkin) code, by controller

Heatcraft intelliGen:

Heatcraft Beacon II: