Thermostats show the model on the back of the faceplate or in the settings menu. Window units put the label on the side of the cabinet. Purifiers and dehumidifiers put it on the base or back.

What Navien Heating, Cooling & Air manuals cover

Terminal labels and wiring
Heat pump settings
Filter replacement
Error and service codes
Installation clearances

Common jobs

Wiring

Wiring diagrams and terminal labels

Thermostats, doorbells, chargers

Maintenance

Maintenance schedules and cleaning steps

Filters, descaling, cleaning schedules

Error codes

Appliance and device error codes, explained

What the letters and numbers mean