I have an RSF Opel high efficiency wood burning fireplace that is rated to heat a 3000 sq. ft. home. The manufacturer offers many options to spread the heat around a house, including an option to tie-in to the plenum for circulation throughout the entire house duct system.

The installation instructions are located here, but the diagram on page 6 is particularly interesting:

The kit does not come with the actual part that connects to the plenum, but the RSF engineer told me it needs to be installed so that the air from the fireplace enters at a 45 degree angle; this is accomplished by installing a deflector.

What are the thoughts of the professionals on here?

Thanks in advance for your help.