Lennox Hearth MLDVT-30NE, MLDVT-30NM, MLDVT-30PM, MLDVT-35NE, MLDVT-35NM, MLDVT-35PM, MLDVT-40NE, MLDVT-40NM, MLDVT-40PM, MLDVT-45NE, MLDVT-45NM, MLDVT-45PM ,

21

NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.

V

H

H1



Wall Firestop/Spacer

(SV4.5HF)



Wall Firestop/Spacer

(SV4.5HF)

Whenusing Secure Flex,

use Firestop/Spacer

SF4.5HF. 

Ceiling

Firestop/Spacer

(SV4.5VF)

Note - When using

Secure FlexTM, use

Firestop/Spacer SF4.5VF.

Table E

H + H1 Maximum V Minimum

feet (meter) feet (meter)

3 (0.914) Elbow Only

5 (1.524) 1 (0.305)

10 (3.048) 2 (0.610)

15 (4.572) 3 (0.914)

20 (6.096) 4 (1.219)

V + H + H1 = 60 feet (18.3 m) Max.

H + H1 = 20 ft. (6.096 m) Max.

Figure 33 - Top Vent - TWO 90-DEGREE ELBOWS

LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MODELS MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS

See Table 8 on Page 20 as an aid in venting

component selection for a particular range of

exterior wall thicknesses.

HORIZONTAL VENT FIGURES / TABLES (continued)

Example: If 20 feet of (H + H1) horizontal vent run is needed,

then 4 feet minimum of (V) vertical vent will be required.

This table shows a 1(V) to 5(H) ratio. For every 1 foot of (V)

vertical, you are allowed 5 feet of (H+ H1) horizontal run, up

to a maximum horizontal run of 20 feet.

An elbow is acceptable as 1 foot of vertical rise except where

an elbow is the only vertical component in the system. See

Figure 31.

Typical termination shown.

Contents

Main INSTALLATION INSTRUCTIONS WARNING /AVERTISSEMENT/AVISO Page Page Figure 2 - Table 2 Figure 1 - Table 3 Table 4 Figure 3 - Typical Locations LOCATION COLD CLIMATE INSULATION MANUFACTURED HOME REQUIREMENTS Figure 5 Side Elevation View Vertical Vent Termination Clearances Figure 4 - Multiple Terminations Termination Kit Termination Kit EXTERIOR HORIZONTAL VENT TERMINATION CLEARANCE REQUIREMENTS A X Figure 7 Figure 9 - Figure 10 - MINIMUM CLEARANCES TO COMBUSTIBLES Appliance And Vent Clearances Figure 8 - Table 5 Figure 12 - Nailing Flanges PRE-INSTALLATION STEPS DETAILED INSTALLATION STEPS Step 1. FRAMING TYPICAL INSTALLATION SEQUENCE 10 FIREPLACE AND FRAMING SPECIFICATIONS Right Side View Top View M H FIREPLACE FRAMING SPECIFICATIONS Figure 15 - Route Gas Line Table 6 Proper Sizing of Gas Line Step 2. ROUTING GAS LINE Step 3. INSTALL THE VENT SYSTEM General Information Figure 16 TRAHCHTGNELNOITCESTNEV TRAHCHTGNELNOITCESTNEV Figure 17 Figure 19 Figure 18 Figure 20 Figure 21 Figure 22 - Roof Framing Figure 24 Figure 23 u Figure 25 u Figure 26 v v VERTICAL VENT FIGURES/TABLES Notes: u u v Figure 27 - Top Vent - THREE ELBOWS VERTICAL VENT FIGURES/TABLES u Figure 28 Figure 30 Figure 29 - Installing Horizontal Termination u HORIZONTAL VENT FIGURES/TABLES Notes: Figure 32 WARNING Figure 33 HORIZONTAL VENT FIGURES / TABLES Figure 34 HORIZONTAL VENT FIGURES / TABLES Figure 35 Figure 36 Step 4. FIELD WIRING Figure 37 Figure 38 CAUTION (In Canada, the current CSA C22-1 Canadian Electrical Code). BLOWER CONTROL CIRCUIT WIRING 120V, 60HZ, 1PH Figure 39 - Step 5. WIRING: OPTIONAL FORCED AIR BLOWER KIT Figure 41 Step 6. CONNECTING GAS LINE Figure 42 Gas Valve Gas Solid Line Connector 1/2" x 3/8" Reducer Gas Stub 1/2" x 3/8" Flare Shut-off Valve WARNING Never use an open ame to check for leaks. Figure 44 Step 7. VERIFYING APPLIANCE OPERATION Figure 43 Page MLDVT-30 & MLDVT-35 LOG PLACEMENT (model-35 shown; model-30 similar) MLDVT-40 & MLDVT-45 LOG PLACEMENT (model-40 shown; model-45 similar) Step 9. INSTALLATION AND REMOVAL OF GLASS DOOR Step 10. BURNER ADJUSTMENTS Flame Appearance and Sooting Figure 49 Do not operate appliance with the glass front removed, cracked or broken. Page Step 11. HOOD INSTALLATION FINISHING REQUIREMENTS - Wall Details Figure 53 See Page 5 for Cold Climate Insulation and Page 8 for Clearances APPOSITION DES MISES EN GARDE RELATIVES LA SCURIT DUTILISATION Figure A Figure B Figure C COLOCACIN DE ADVERTENCIAS DE SEGURIDAD EN OPERACIN ATTACHING SAFETY-IN-OPERATION WARNINGS SAFETY LABEL DIAGRAMS DIAGRAMAS DE ETIQUETAS DE SEGURIDAD INSTALLATION ACCESSORIES Listed Secure Vent Components Cat. No. Model Description 36 Cat. # Model Description Listed Secure Vent Components Cat. # Model Description INSTALLATION ACCESSORIES CONTINUED * Page Figure 55 Millivolt Appliances Figure 56 Figure 57 Figure 59 VERIFY THE PROPER ORIFICE SIZE BEFORE INSTALLING IT. Figure 60 Table 9