The A421 Series Electronic Temperature Controls are the next generation of the A419 Series Electronic Temperature Controls.
If you need to replace an A419 Control with an A421 Control, be sure to note that wiring terminals on the TB1 and TB2 terminal blocks on A421 Controls are in different positions and have different terminal labels from the wiring terminals on the A419 Controls. Table 1 provides a cross-reference for matching the terminal labels on A419 Controls to the terminal labels on A421 Controls.
See Figure 2 for terminal block and terminal positions on the A421 Control.
|A419 Terminal label
|A421 Terminal label