36 NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Flex
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MODELS MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
Cat. # Model Description
H1969 SF4.5HT-2 Horizontal Square Termina-
tion for flex (without ex)
77L87 SFKIT12S Square Term. for flex
(with 12 inch [305 mm]*
compressed ex)
77L88 SFKIT18S Square Term. for flex
(with 18 inch [457 mm]*
compressed ex)
77L89 SFKIT24S Square Term. for flex
(with 24 inch [610 mm]*
compressed ex)
77L90 SFKIT36S Square Term. for flex
(with 36 inch [914 mm]*
compressed ex)
77L91 SFKIT48S Square Term. for flex
(with 48 inch [1219
mm]* compressed ex)
94L04 SFKIT12SS Small Square Termination
for flex, with 12 in. (305
mm) of *compressed ex
vent (ref. Instr. P/N 750204M)
94L05 SFKIT18SS Small Square Termination
for flex, with 18 in. (457
mm) of *compressed ex
vent (ref. Instr. P/N 750204M)
94L06 SFKIT24SS Small Square Termination
for flex, with 24 in. (610
mm) of *compressed ex
vent (ref. Instr. P/N 750204M)
94L07 SFKIT36SS Small Square Termination
for flex, with 36 in. (914
mm) of *compressed ex
vent (ref. Instr. P/N 750204M)
94L08 SFKIT48SS Small Square Termination
for flex, with 48 in. (1219
mm) of *compressed ex
vent (ref. Instr. P/N 750204M)
94L09 SF-HTSS Horizontal S mall Square
Termination for flex, without
flex vent (ref. Instr. P/N 750204M)
56L74 SFVT30 Vertical Termination for
flex (at to 6/12) with ex
adaptor, section of rigid
vent, roof support collar
assembly, roof flashing
and storm collar.
(ref. Instruction P/N 750052M)
56L75 SFVT45 Vertical Termination for
flex (6/12 to 12/12) with
flex adaptor, section of
rigid vent, roof support
collar assembly, roof
flashing and storm collar.
(ref. Instruction P/N 750052M)
91L66 SFGC4-6 Gear Clamp 4.5 in. (114
mm) for flex (6-pack)
91L67 SFGC7-6 Gear Clamp 7.5 in. (190.5
mm) for flex (6-pack)
H7748 FVK36 36"
Flex
Connector Kit
Note: Flex attaches to
appliance collar at one end
and to rigid venting at other
end.
Listed Secure Vent™ Components
Cat. # Model Description
17M52 SV4.5HGS-1 Termination Guard, Square
(1-pack)
(ref. Instruction P/N 750109M)
17M53 SV4.5HGS-12 Termination Guard, Hori-
zontal Square (12-pack)
(ref. Instruction P/N 750109M)
87L02 SV4.5HGS Termination Guard for
Horizontal Square Termi-
nation (Deluxe) (1-pack)
(ref. Instruction P/N 750055M)
H5820 SV4.5HTSK Termination Shroud
(Guard) for Horizontal
Square Termination
(1-pack)
(ref. Instruction P/N 750246M)
H5816
750,247M
SV4.5-
TWSK10 Through Wall Shield Kit
(used to shield the direct-
vent pipe from blown
insulation)
(ref. Instruction P/N 750247M)
H3907 SV4.5ARSA Attic Insulation Shield w/
adjustable height, 12"-22"
96K93 SV4.5SU Support Strap
10K81 SFMP Mill-Pac, Black, High
Temperature Sealant
89L40 SFMP-12 Mill-Pac, Black, High
Temperature Sealant -
Bulk 12-pack
99L02 SV4.5HRK14 Horizontal Riser Kit, 14"
(ref. Instruction P/N 750146M)
99L03 SV4.5HRK36 Horizontal Riser Kit, 36"
(ref. Instruction P/N 750146M)
H1988 CTSA-33
Chase Top Shroud Kit, Arch
Top 3 X 3 Ft.
(ref. Instruction P/N 750194M)
H1985 CTSO-33
Chase Top Shroud Kit,
Open Top 3 x 3 ft.
(ref. Instruction P/N 750193M)
H1987 CTSO-44
Chase Top Shroud Kit,
Open Top 4 x 4 ft.
(ref. Instruction P/N 750193M)
H1986 CTSO-46
Chase Top Shroud Kit,
Open Top 4 x 6 ft.
(ref. Instruction P/N 750193M)
Listed Secure Flex™ Components
These termination kits include firestop/spacer, gear clamps and flex adaptor.
60L10 SF-18 18 feet (5.49 m) *
compressed flex
(ref. Instruction P/N 750053M)
98K03 SF-12 12 feet (3.66 m) *
compressed flex
(ref. Instruction P/N 750052M)
H2248 SF4.5HF-10 Firestop/Spacer-Horizontal
,
flex
(3-1-1 spacing)
,
10-Pack
H2249 SF4.5VF-10 Firestop/Spacer-Vertical,
flex (1-1-1 spacing)
,
10-Pack
INSTALLATION ACCESSORIES CONTINUED*All compressed flex vents can be expanded up to two times.
Se
a
l
a
nt
(Fits H1968)
(Fits 94L10
& H1968)
(Fits 94L10
& H1968)