Tech Tips: Wiring a Power Module

Here we can see the back of our low voltage thermostat and our power modules. If you look at the power module covers, you can see that there's an on/off switch underneath in the center. Always make sure that those are turned on, otherwise your system won't work correctly. You can take the faceplates off and when you take the faceplates off, you can see how the connections are made.

Here we can see the back of our low voltage power supply is mated first with power module number 1. You always get power module number 1 and the low voltage thermostat working correctly together first. The connections between this one and this one is a 12 volt, a drive, and a ground. 12 volt, ground and drive.

When you add power module number 2 and number 3 and number 4 etc., you can go up to 10, you can see that our connections are only going to be between the drive and the ground. We do not use the 12 volt DC. It's only used for the first power module to the 12 volt DC thermostat. All the other connections only require 2 wires; drive and ground.

Here we can get a little bit better shot of the wires as they connect to the back of the master thermostat. We have 2 connections here; that's for the floor sensor. Then I've used green for ground, yellow for drive, and black for 12 volt DC. If we take a look over at the power module, we can see that we have the corresponding connections made here. This is the connection between power module 1 and the master thermostat. Connections between power module 1 and power module number 2 are only going to consist of ground and drive. You do not connect 12 volt DC between the power modules.

Here we can see that we have black in 12 volt DC, number 2 is ground, number 3 is drive. The problem with this is, a lot of people make the mistake of going between 1, 2, and 3, but they don't really need to do 1, 2, and 3. They need to go by colors. If you look at the master thermostat again, you'll see that 12 volt DC is actually the first position. Drive, which is yellow, is in the second position. Ground is in the third position. Well, they don't land that same way over on the power module; they go, black, green, and yellow instead.

If we take a look at the connection once again between power module 1 and power module number 2, remember we do not connect 12 volt DC between these 2. All we're connecting is the ground and the drive.