HVAC Ladder: Wiring Diagrams

Draw professional HVAC ladder diagrams right on your phone — built by a working HVAC tech, for the techs in the trade.

HVAC Ladder is a fast, finger-first editor for electrical ladder diagrams and wiring schematics. Sketch a control circuit in the truck, document a repair before you leave the roof, or teach a class how a heat pump actually sequences — then export a clean, print-ready diagram.

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
• The diagram scales to your screen — phone, tablet, portrait or landscape
• Undo, autosave, and crash recovery protect every change

A REAL HVAC SYMBOL LIBRARY
• Contacts, push buttons, and relays
• Pressure switches, thermostats, flow, float, and limit switches
• Motors, compressors, heat elements, transformers, capacitors, start relays
• Multi-terminal thermostat block (R, G, Y, W, C and more) and a Hand-Off-Auto selector block
• Tap any symbol to see its full name and plain-English meaning — great for apprentices

EXPORT & SHARE
• Black-and-white PNG and vector PDF exports with a title block: project, equipment, name, and date
• Diagrams print clean — black on paper, like a real schematic
• Share the editable diagram file itself; it opens on any device running HVAC Ladder

BUILT FOR THE FIELD
• 100% offline — no account, no sign-in, no ads
• We collect nothing. Your diagrams stay on your device, period
• Dark mode for attics and equipment rooms, light mode for daylight

TEACHING & LEARNING
• Guided tour walks you through wiring a fan control with a transformer
• Built-in symbol glossary and a full illustrated manual
• Ready-made example circuits: heat pump with defrost, walk-in cooler, air compressor, start-stop with indicator light
• Instructors: sketch a circuit live in class; students: label every component as you learn it

WHO IT'S FOR
HVAC technicians documenting control wiring in the field. Apprentices learning to read a ladder diagram. Instructors teaching electrical schematics. Facility and refrigeration techs who need a wiring diagram that matches what's actually in the panel.

Made by HVAC Mobile — a working technician who wanted a ladder diagram app that speaks the trade's language. Questions or ideas? There's a direct email link inside the app; real feedback from real techs shapes every update.

Recent changes:
Symbol flash cards and some other small fixes.