HVAC Refrigeration Guide — troubleshooting

Trane LED Flash Codes, Storm-Damaged Top Covers & CleanEffects Filter Failures: Field Diagnosis Guide

Jul 22, 2026

Heat domes, hailstorms, and wildfire smoke are driving three failure patterns on Trane systems this summer: pressure switch faults triggering 3-flash LED codes, storm-cracked condenser top covers exposing fan motors, and saturated CleanEffects ifD cells choking airflow. This field guide covers how to diagnose each one and which confirmed OEM parts — SWT3926, COV5617, and FLR6453 — fix them on the first trip.

Tags: Air Handler, CleanEffects, Condenser, COV5617, Flash Codes, FLR6453, Furnace, HVAC, OEM Parts, Pressure Switch, Storm Damage, SWT3926, Trane, Troubleshooting, Wildfire Smoke

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

Johnson Controls Actuator Field Guide

Jul 01, 2026

Johnson Controls actuators, zone valves, and sensors are the backbone of commercial HVAC controls. This field guide covers VA/VG series failure patterns, wiring gotchas, and the parts professional technicians stock for fast turnaround.

Tags: actuators, building automation, commercial HVAC, control valves, diagnostics, HVAC, Johnson Controls, pressure transducers, temperature sensors, troubleshooting, VA series, VAV, VG series, zone valves

Lochinvar AO Smith Field Guide

Jun 28, 2026

Lochinvar commercial water heater troubleshooting: why burner door switches trip, what causes burner soot and flame failure, and when to replace the relief valve.

Tags: 100111113, 100274785, 100292715, AO Smith, burner assembly, commercial boiler, commercial water heater, door temperature switch, field guide, FVIR, HVAC parts, Lochinvar, lockout, OEM parts, pressure relief valve, soot, troubleshooting

Run Capacitor Field Guide

May 27, 2026

Run capacitors fail silently and take compressors and fan motors with them. This field guide covers failure mechanisms, accurate testing procedures, MFD tolerance rules, and stocking strategy for HVACR technicians.

Tags: 370V, 440V, capacitor replacement, capacitor testing, compressor, condenser fan motor, dual run capacitor, field guide, HVAC, HVACR, MFD, motor capacitor, run capacitor, troubleshooting, truck stock