Remote Blower unit

[sd4524]

Hello All
I have learned a great deal reading through old threads and decided to post a question. I do only residential work and my understanding of motors is not where it needs to be. Trimming out a kitchen fan hood with a remote blower unit on the roof of a brand new home. The blower on the roof is a Thermador brand (already installed during rough) and the Hood is a Viking brand. They are not made to go together but this fact got by everybody during rough-in and design. There is 120v at the fan hood and then 5 wires from the hood to the blower unit on the roof (One for high speed, Medium speed, low speed, neutral, ground.
The fan hood has a dial that appears to have 10 positions on it for different speeds. Viking remote blowers would only require hot,neutral, ground.
Is the motor on the remote blower only supposed to run at theses 3 speeds. If I wired so that high speed is used w/ hood dial will the motor burn up? I think it will.
Lastly, how would you explain to gc WHY the motor will burn up. Besides changing the units to matching brands, any suggestions on a switch or dial that could be mounted under fan hood.

 

[LarryFine]

Viking remote blowers would only require hot,neutral, ground.

If I wired so that high speed is used w/ hood dial will the motor burn up?

It's hard to say, but that would be the way to wire it. You have two hurdles: the fan maker can blame the dial control if it burns up the motor, and the dial maker can blame the motor if it fails.

You need to get at least one of them to okay the combination, or else one of the units should be replaced to make a complete system. Either way, don't let it become your burden or responsibility.