No. Per the sizing tables, all orientations must terminate vertically with a UL listed rain cap, otherwise the appliance may not vent properly.

How far can you run B vent horizontal?

The rule is 2/3rds of the vertical height of the vent. So if the vent is 30' high you can run the horizontal pipe 20' if you can maintain the 1/4" gradient needed to the vertical.

Can a vent pipe run horizontally?

2. Can Vent Pipes be Horizontal? There is no problem with running your vent pipes horizontally as long as you remember that there should be a minimum clearance of 6 inches above the spill line. ... Keep this clearance in mind and you should have no problem with horizontally installed vent pipes.