Monessen Hearth DIRECT VENT MLDV500 - Manual (Page 18)

18 75D0004
MLDV Series Gas Fireplace
• The maximum number of 90° elbows per side wall installation is three (3). Figure 20
• If a 90° elbow is fitted directly on the top of the fireplace, the maximum horizontal vent run before
the termination or a vertical rise is 36” (914 mm). Figure 21
VENTING INSTALLATION
HORIZONTAL WITH VERTICAL RISE (THROUGH-THE-WALL)
TERMINATION CONFIGURATIONS
Since it is very important that the venting system maintain its balance between the combus-
tion air intake and the flue gas exhaust, certain limitations as to vent configurations apply
and must be strictly adhered to.
The Vent Graph, showing the relationship between vertical and horizontal side wall venting, will help
to determine the various dimensions allowable. Figure 13
Minimum clearance between vent pipes and combustible materials is 3" on top and 1" from bottom
and sides unless otherwise noted (Exception: Outside wall with firestop: 1" all around pipes are
allowed). If the vertical run is 7
1 /

feet or more, off the top of the fireplace, the clearance is 1" on all
sides of the horizontal run.
When vent termination exits through foundations less than 0" below siding outcrop, the vent pipe
must be flush with the siding.
It is best to locate the fireplace in such a way that minimizes the number of offsets and horizontal
vent length.
The horizontal vent run refers to the total
length of vent pipe from the flue collar
of the fireplace (or the top of the Transi-
tion Elbow) to the face of the finished
outside wall or the mounting flange of
the termination.
FP1176
max 90 bends
Figure 20 -
Maximum Three (3) 90° Elbows Per Installation
3 x 90°
Elbows
3 x 90°
Elbows
FP1176
Max 20"
Max 20"
36"
(914 mm)
Max.
36"
(914 mm)
Max.
FP1177
max horizontal run
Figure 21 -
Maximum Horizontal Run with
No Rise
FP1177
W
ARNING
When installing the appliance as a rear vent unit, the 90° or
45° transition elbow attached directly to the rear of the unit
is NOT INCLUDED in the following criteria and calculations
and, unless specifically mentioned, should be ignored when
calculating venting layouts.