Preliminary Voltage Checks
1-Wire Indoor Interface/Sensor Kit

In the following, be careful not to short any connection while probing with your multimeter. You should also be aware that a protection diode is on the power supply input to the board. If reverse polarity is applied, the diode will conduct, shorting the power supply. Therefore, when you apply power for the first time in the next step, check the voltage very quickly to be sure you get a reading. If not, immediately remove power and find the cause before continuing.

Ok
Procedure
  Connect the DC power source to the power jack and measure the voltage across D4 with the positive lead to the cathode (banded end) and the negative to the anode. You should read a voltage in the range of 14-18 VDC. If not, immediately disconnect the power and find the problem before continuing with the next step.
  With the negative meter lead connected to the anode of D4 (same as above), +12V should be read at the ‘+12’ position at P19.
  In like manner, with the negative meter lead still connected to the anode of D4, +5V should be read at the ‘RG’ position at P1.

Again, if you fail to get any of the above readings, you must find and fix the problem before proceeding.

Next