HVAC Ladder: Wiring Diagrams

New in 1.4: tap any symbol to learn its full name and meaning, Hand-Off-Auto with an OFF indicator output, and a smoother iPad experience. Built by a tech, for techs.

HVAC Ladder lets you draw clean wiring and electrical control ladder diagrams right on your phone or iPad — standing at the unit, in the truck, in class, wherever you are. Tap a symbol from the library, drop it on a rung, label it, done. Export a PDF or PNG and send it to the apprentice, another tech, the teacher, or the shop.

DRAW IN SECONDS • Hold and drag symbols straight onto numbered rungs • Real ladder layout: L1/L2 rails, an L3 leg for three-phase loads, parallel branches • Undo, autosave, and crash recovery protect every change • The diagram scales to fit your screen — iPhone or iPad, portrait or landscape

THE SYMBOLS YOU ACTUALLY USE • Contacts, push buttons, relays, and coils • Pressure switches, thermostats, flow, float, and limit switches • Motors, compressors, transformers, capacitors, start relays, heat elements • Multi-terminal thermostat block (R, G, Y, W, C and more) and a Hand-Off-Auto selector with an optional OFF indicator output

LEARN IT. TEACH IT. • Tap any symbol to see its full name and plain-English meaning — no abbreviation left unexplained • Guided tour wires up a real fan control with a step-down transformer, step by step • Built-in symbol glossary and a full illustrated manual — study offline anywhere • Example circuits to explore and modify: heat pump with defrost, walk-in cooler, air compressor, start-stop • Instructors: build a circuit live in class and export it as a handout

EXPORT & SHARE • Clean black-and-white PNG and vector PDF with a title block: project, equipment, name, date • Prints like a real schematic — black on paper • Share the editable diagram file; it opens in HVAC Ladder on iPhone, iPad, Android, and Windows

PRIVATE BY DESIGN • 100% offline — no account, no sign-in, no ads • We collect nothing; your diagrams stay on your device

Made by a working HVAC tech for the techs in the trade — and for the apprentices, students, and instructors learning it. Real feedback from the field shapes every update.