Wiring of a VFD Fan Board at the J1 and J2 Plugs to VFD drive and to CTRL board

When you get a new VFD drive and want to install it and you see that the other one was already taken out by someone else and you are not familiar with the wiring of the drive then this will help you get the basic wiring out of the way for the specific drives listed below. By doing this you will prolong the life of the motors and equipment by using the VFD drive vs bypassing the drive which we do not recommend!

If for any reason you decide to bypass the drive, then you must follow Carriers temporary bypass instructions on Figure 4 and 5 of this article. The purpose of the bypass instructions is to avoid damaging the motors that do not have internal motor protection inside them.

NOTE: Use CTRL Button on keyboard plus your mouse wheel to increase or decrease image sizes on the Figures below.

If you notice on Figure 1 is a graphic to give you an idea of what is happening inside the board. The 24vac signal from the Control Board determines if it is a G/Y1 for low speed at 40hz or Y2/W for High speed at 60hz.

When the 24vac (AC) signal comes into the J1 Plug from the Control Board or CTB, it energizes the relays on the board to allow the 24vdc (DC) voltage that is generated by the VFD drive to allow the voltage through the pink wire on 24DVC on the J2 plug and then goes through the yellow wire which is Low or the white wire which is High on the relays as pictured in Figure 1, which then determines which speed the drive will run at. The settings of the drive then determine the speeds setup for it to run. In this case we used 40hz for Low speed and 60hz for High speed. If the drive is wired incorrectly then you will have issues with it working properly.