HVAC Refrigeration Guide — contactor

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

York HVAC Parts Field Guide

Jun 21, 2026

York parts field guide for HVAC techs — confirmed OEM replacements including the S1-6008081 condenser motor, S1-373-20830-001 inducer, and S1-THEC11NS thermostat, with diagnostic sequences and failure patterns.

Tags: Coleman, commercial HVAC, condenser fan motor, contactor, draft inducer, dual-run capacitor, Evcon, field guide, furnace lockout, HVAC diagnostics, HVAC technician, Johnson Controls, Luxaire, OEM replacement parts, pressure switch, residential HVAC, rooftop units, run capacitor, S1-373-20830-001, S1-6008081, S1-THEC11NS, Source 1, thermostat, York, York OEM parts

HVAC Contactor Failures

May 31, 2026

HVAC contactor failures are one of the most misdiagnosed calls in commercial HVAC. This field guide covers burn patterns, coil voltage matching, contact pitting diagnosis, and what to stock before peak season hits.

Tags: coil voltage, commercial HVAC, compressor, contact pitting, contactor, contactor failure, field service, HVAC, HVAC diagnostics, HVAC repair, HVACR, OEM parts, residential HVAC, welded contacts

Lennox Parts Field Guide

May 24, 2026

Lennox HVAC parts field guide for professional technicians — capacitors, contactor failures, condenser fan motors, control boards, and OEM part numbers. Stock smarter, diagnose faster.

Tags: Capacitor, Condenser Fan Motor, Contactor, Control Board, Field Guide, HVAC, iComfort, Lennox, OEM Parts, Pressure Switch, Summer HVAC, Troubleshooting, XC16, XC20, XC21

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