Install Instructions

A421 Series Standard Electronic Temperature Controls Installation Instructions
5
Table 2: A421 Control Wiring Terminals and Wire Size Information (Part 1 of 2)
Terminal
Block
Label Description, Function, and Requirements Recommended
Wire Sizes
TB1
24 VAC
Models
LN Low-Voltage 24 VAC Control Power (Common): Connect the 24 VAC
supply power to operate the control.
28 AWG to 12 AWG
0.08 mm
2
to 4.0 mm
2
24V Low-Voltage 24 VAC Control Power (Hot): Connect 24 VAC supply
power to operate the control (via jumper from LC in Figure 4).
TB1
120/240 VAC
Models
LN Line-Voltage Power Source (Common): Connect the neutral wire for 120
VAC supply power applications. Connect the L1 supply power lead for all
208/240 VAC supply power applications.
28 AWG to 12 AWG
0.08 mm
2
to 4.0 mm
2
120V Line-Voltage 120 VAC Control Power (Hot): Connect the 120 VAC
supply power (hot) for 120 VAC supply power applications (via jumper from
LC in Figure 4).
240V Line-Voltage 240 VAC Control Power (L2) Terminal: Connect the L2
supply power connection for 208/240 VAC supply power applications (via
jumper from LC in Figure 4).
TB2 LC Line-Voltage SPDT Relay Common Contact: Connects power supply to
power the controlled load. Connect 24 VAC (hot) for 24 VAC applications;
120 VAC (hot) for 120 VAC applications’ and L2 for 208/240 VAC
applications.
28 AWG to 12 AWG
0.08 mm
2
to 4.0 mm
2
LNO Line-Voltage SPDT Relay Normally Open Contact: Connects controlled
equipment to the Line-Voltage Normally Open (LNO) contact on the SPDT
relay. When LC is closed to LNO, the relay is energized and the green LED
is on. The LNO terminal typically provides power to the controlled
equipment in both cooling and heating applications.
LNC Line-Voltage SPDT Relay Normally Closed Contact: Connects
controlled equipment to the Line-Voltage Normally Closed (LNC) contact
on the SPDT relay. When LC is closed to LNC, the relay is de-energized
and the green LED is off. The LNC terminal is not typically wired to the
controlled equipment.
Figure 4: Wiring the A421 Series Controls Using the Same Power Source
to Power the Control Operation and Power the Controlled Equipment