Mendota ML39 Assembly, Installation And Operating Instructions page 37

Side by Side installation of two Vent Caps
When two or more vertical vent caps are located within proximity of one another, it is required that a galvanized steel 18-gauge
or heavier barrier wall be installed between the two vent caps to eliminate recirculation of exhaust gases from one cap to
another.
The galvanized steel barrier shall be 6" taller than the highest point of the vent caps and shall be 3" wider past the outer edges of
the vent caps.
If two gravity direct vent system gas appliances are terminated next to each other, the minimum required distance between the
vertical center line of the vent caps is 18" to prevent recirculation of exhaust from one vent cap outlet into the air intake of
another vent cap.
If a wood burning flue opening is adjacent to a gravity direct vent system gas appliance vent cap and the distance between
vertical center lines of the two terminations is less than 36", we recommend a metal divider plate be installed to prevent wood
burning exhaust from entering the gas appliance air intake path. Alternatively, you may also vertically extend the wood burning
flue liner up 24" higher than the top surface of the gas appliance vent cap.
Figure 3-25 Side by Side Vent Caps
85-03-01136 ML39 Page 37