The power board is capable of controlling a second housed sensor. The second sensor, model D4S, can be wired to the power board per the following:
1. Connect wires to the four wire terminals in the corner of the D4S sensor housing designated as Tamper (Y,Y), +R, and –B. Route wires through the conduit openings in the sensor housing and D4240 power board housing.
2. Connect the opposing ends of the wires to the terminal connections marked “Sensor 2” on the Power board. See Figure 6 for reference. Ensure that wires are connected to the appropriate terminal locations. A No. 0 or 1 phillips screwdriver should be used for terminal connection. The tamper terminals are not polarity sensitive.
3. Adjust the middle dip switch on the power board to indicate (2) sensors as shown in Figure 6.
4. The D4S can only be used with new InnovairFlex models and is not compatible with previously sold detectors.[9] Unit Configuration: