What are the Brown and Blue wires on the Universal System?

In HVAC systems, L1 and L2 are the main power terminals where you connect the incoming power supply. These terminals are usually clearly labeled on the bus bar or terminal block inside the unit.

• Typically, the brown wire is used for the live (L1) connection.

• The blue wire is often used for the neutral (L2) connection.

⚠️ Important:
Always verify wiring using the unit’s specific wiring diagram, as colors and terminal labeling can vary between models and manufacturers.

Note:
On newer units, the traditional L1 and L2 terminal labels have been phased out. Now, you will usually just see a brown and blue wire, which are intended to connect to two hot wires that go directly to the breaker. Both wires are energized, and there is no true neutral like in standard household wiring.