Heatcraft Walk-In Controller Codes: Beacon II, Smart, intelliGen

Heatcraft makes walk-in refrigeration under the Bohn, Larkin, Climate Control and Chandler names, and many of those systems use one of three Heatcraft electronic controllers. Each speaks its own code language. This page helps you tell them apart and read their codes straight from Heatcraft's manuals.

For general Heatcraft system troubleshooting (not controller codes), see the site's Heatcraft walk-in cooler troubleshooting guide. For what these controllers do, see Heatcraft smart systems.

Which Heatcraft controller do you have?

The controller is usually mounted on the evaporator (the fan-coil unit in the box) or on a remote display near the door. The code style is the quickest clue:

Confirm with the label on the controller or evaporator. If none of these match, your walk-in may use a third-party controller (see Dixell and Carel codes) or a mechanical thermostat.

Before you reset anything

A few rules protect both the equipment and your warranty:

• Write down the code first, photograph the display, and note the box temperature from a separate thermometer.
• Don't power-cycle to clear a lockout unless you understand why it tripped. On Beacon II, the A3 start-up failure alarm appears after 4 unsuccessful restarts and clears through Service mode or power cycling. Clearing it without fixing the cause just puts the compressor through more failed starts.
• Don't reset compressor shutdown codes (Beacon II E7, Smart Controller SHTDN) more than the manual allows. They mean a high-pressure, low-pressure or oil pressure switch opened. See pressure controls.
• Don't change setpoints or parameters to "fix" an alarm. Adjusting alarm limits or defrost settings hides the symptom.
• Leave electrical covers closed. Heatcraft states that installation and maintenance are to be performed only by qualified personnel.

Safety: The evaporator and condensing unit contain line-voltage wiring and fans that can start without warning. Staff should read the display and check breaker and disconnect positions only.

Beacon II codes

Source: Heatcraft Beacon II manual H-IM-79G (Jun 2020), pp.12, 15, 17–18.

Beacon II errors

Beacon II alarms

Defaults worth knowing: the alarm time defaults to 60 minutes. The high alarm limit defaults to +50°F on air-defrost (cooler) systems and +5°F on electric-defrost (freezer) systems; the low limit defaults to +30°F and −15°F. So on a default cooler, A1 means the box has been above 50°F for an hour, well past the 41°F cold-holding limit in the FDA Food Code. Treat A1 as a product emergency, not just an equipment alarm. See food safety when a walk-in fails.

Display modes (normal, not faults): oFF, Coo (cooling), Pdn (pump-down), dEF (defrost), drn (draining), plus dLY, tSt and SEr (see the mode table in the manual), and Loc/UnL (locked/unlocked).

Other factory defaults from the manual: box setpoint 35°F (air defrost) or −10°F (electric defrost); defrosts 2 per day (air) or 4 per day (electric); defrost termination +45°F (air) or +60°F (electric); fail-safe 40 minutes (air) or 30 minutes (electric). After an electric defrost, the controller holds a 2-minute drain-down, then a refreeze with the fans off until suction reaches 28°F or 3 minutes pass. That fan delay is why the fans stay off briefly after defrost.

Smart Controller codes

Source: Heatcraft Smart Controller manual H-IM-80F (Jul 2017), pp.10–11.

Smart Controller errors

Smart Controller alarms

When an alarm is active, the display shows "CALL FOR SERVICE," the buzzer sounds and the controller's dry alarm contacts close. Those contacts are rated 125 VAC / 1 A and can be wired by a technician to a monitoring system. See walk-in temperature monitoring.

The Smart Controller's "Smart Defrost" programs 8 defrost opportunities per day, with a 55°F termination and a 60-minute fail-safe, so seeing defrost more often than on older timers is normal on this controller.

intelliGen codes

Source: Heatcraft intelliGen Refrigeration Controller manual (H-IM-iRC, Feb 2025), p.43.

Light bar: green = normal; yellow = an error somewhere on the system (the unit at fault flashes); red = an alarm (the unit at fault flashes).

intelliGen errors

intelliGen alarms and information codes

The ER32–ER37 and AL12 codes relate to A2L (lower-flammability) refrigerants. If any A2L code appears with a leak warning, get people out of the box and follow refrigerant leak safety. IN05 means eight defrosts in a row ended on time rather than temperature, which often points to coil icing; see evaporator coil frozen.

Heatcraft notes intelliGen may be wired only to Heatcraft-designed condensing units.

What a technician will check

• Sensor faults (E1–E5, BXSEN–ODSEN, ER01–ER04): wiring and the sensor itself. The intelliGen manual gives a check in 32°F ice water: the sensor should read about 32,650 Ω and is replaced if it is more than 1,000 Ω off. Technicians should confirm against the specific controller's table.
• Power supply errors (ER14/ER15) or a blank or rebooting display: control voltage. The Beacon II and intelliGen boards may shut down below 18 VAC, and a 208-V supply requires moving the evaporator transformer tap.
• Low superheat (E6, SUPLO, ER16): expansion valve, sensor placement and charge. Beacon II's default is 7°F at the evaporator, adjustable to keep 20°F to 30°F at the compressor. See expansion valve (TXV).
• Compressor shutdown or start-up failures: pressure switches, condenser airflow, charge and electrical components.

Bring the code, the controller type and your temperature log to the call. See what to tell a refrigeration technician.