3 way fireplace

Hello,
My wife and I are looking at a 3 sided fireplace. We are in the process of getting quotes.

We have had hearth and home come out and two other places that sells Majestic style fireplaces.

The second Majestic dealer said today that it is not possible to place a fireplace in the location we are looking. Neither of the other two locations said there would be an issue so i am confused and maybe somone here can clear this up for me.

My Run is 17-18 feet from the outsdie wall and will require an "Additional" 90. There will be a 90 to go from veritcal to horizontal and then i have to go vertical again and then horizontal. (Make sense?)

The gentleman that came over today said that for 7 feet of rise he can go 18 feet. With this additional 90 that I need i have to reduce my 18 feet number to 15.

What are people's thoughts on this? I don't know if people are telling me the truth as one says i can install this and another says i can't. What are the rules and which 3 way can i install?

Thanks for all of the help.

 

Anyone have any ideas?

Thanks for the help.