Boiler Wiring for Beginners – Full Walkthrough of a Real System (Honeywell L8148E + Zone Valves)

Want to learn how residential boiler wiring actually works? In this video, I completely dismantle and explain the wiring of a real hydronic (water-based) boiler system. You’ll see exactly how the components interact in a classic Crown boiler setup with a Honeywell L8148E aquastat and 4-wire Honeywell zone valves. This is one of the most beginner-friendly boiler wiring videos you'll find — designed to make sense even if you're just starting out in HVAC or tackling a DIY boiler project. 🔧 Covered in this video: – How aquastats work (L8148E focus) – What zone valves do and how they’re wired – Power supply, thermostat signals, and circulator control – Basic boiler logic from call for heat to burner ignition – Troubleshooting tips along the way This is real-world HVAC training for techs, students, and homeowners alike. 00:00 Introduction 00:40 120 Volt Power @ Aquastat 01:36 T, TV, Z and W Terminals 02:25 Zone Valves & Thermostats Overview 03:06 T & T Circuit Concept / Wiring 04:27 Zone Valve Motor Circuit Off Z To TV 06:27 Zone Valve End Switch Circuit Off Z to T 07:06 Aquastat Internal Relays / Controls 08:30 Burner Circuit: Spill Switch, Roll Out, Gas Valve 10:09 Powered Demonstration / Sequence of Operation HVAC / HVAC Training