Monessen Hearth DIRECT VENT MLDV500 - Manual (Page 22)

 75D0004
MLDV Series Gas Fireplace VENTING INSTALLATION
VERTICAL THROUGH-THE-ROOF APPLICATIONS
Install restrictor disc as shown in Figure 29 for vertically vented ap-
plications.
Up to two () restrictor discs may be needed for 40' installation.
The two () restrictor discs suppled will work for most installations.
If a third disc is needed order Part No. 56D307.
You may use a reducer to 4" x 6
B\, " in vertically vented applications.
If a reducer is used, only one restrictor may be used.
NOTICE
A restrictor disc must be installed on
any vertical termination that is higher
than 12'.
FP1967
restrictor disc
Restrictor Disc
Fireplace Collar
FP1967
Figure 29 -
Install Restrictor Disc into Fireplace Collar