HVAC Refrigeration Guide — Refrigeration

Heatcraft Bohn Larkin Unit Cooler Troubleshooting

Jul 19, 2026

HVACR techs: learn how to read Heatcraft IntelliGen alarm codes (AL01, AL06, ER25, ER26) before swapping parts. This guide covers the most common unit cooler faults — high box temp, door open alarms, connection-lost errors, and evaporator fan failure — with confirmed OEM part numbers for the two failures we see most: contactor failure (2259996) and evaporator fan motor failure (25322406).

Tags: 2259996, 25308301S, 25312601S, 25322406, AL01, AL06, alarm codes, Bohn, Chandler, contactor, ER25, ER26, evaporator fan, Heatcraft, high box temp, HVACR, IntelliGen, Larkin, not cooling, R026215300, refrigeration, troubleshooting, unit cooler, walk-in cooler

Condenser Fan Motor Diagnosis

May 13, 2026

A field-tested diagnostic guide for condenser fan motor failures — covering winding failure, bearing seizure, capacitor misdiagnosis, and OEM spec matching. Includes a symptom-to-cause table, step-by-step diagnostic sequence, and brand-specific notes for Trane, Heatcraft, York, and Nordyne.

Tags: bearing failure, commercial HVAC, condenser fan motor, Heatcraft, HVAC, motor diagnosis, Nordyne, OEM replacement, refrigeration, run capacitor, Trane, winding failure, York

Copeland Compressor Protection

May 06, 2026

Copeland compressor failures don't have to be a mystery. This field guide covers how to read CoreSense fault codes correctly, verify crankcase heater function before startup, and diagnose accumulator failures that drive repeat compressor failures — so you replace the right part the first time.

Tags: accumulator, compressor, compressor protection, Copeland, CoreSense, crankcase heater, discharge temperature, fault codes, field guide, filter drier, HVAC, liquid slugging, reciprocating compressor, refrigeration, scroll compressor, suction superheat, troubleshooting, vacuum procedure

HVACR Control Board Diagnosis

Apr 29, 2026

A misdiagnosed control board replacement is one of the most expensive mistakes a technician can make — not because the board is wrong, but because the board was never the problem. This guide covers the failure mechanisms, diagnostic protocol, and replacement discipline for HVAC control boards and defrost boards across the multi-brand commercial environment most technicians actually work in.

Tags: commercial-hvac, control-board, daikin-mcquay, defrost-board, friedrich, hvac-diagnostics, hvacr, nordyne, oem-parts, pcb-repair, refrigeration, troubleshooting

The Cooling Season Startup

Apr 26, 2026

The pre-season maintenance window is closing fast. Before ambient temperatures push past 95°F, the diagnostic window shifts from planned to emergency — and every callback costs money. This guide covers the high-ambient failure cascades that define cooling season: head pressure death spirals, capacitor degradation under thermal stress, contactor burnout, and crankcase slugging on first startup. Learn the precise intervention points that separate a spring PM call from a July compressor replacement.

Tags: Capacitor, Compressor, Condenser Fan Motor, Contactor, Cooling Season, Crankcase Heater, Field Service, Heat Wave, High Ambient, HVAC, HVACR Tips, OEM Parts, Preventive Maintenance, Refrigeration, Spring Startup