Lennox Montebello DLX Installation Instructions Manual page 32

LENNOX HEARTH PRODUCTS • MONTEBELLO
Step 6. Refer to the instructions provided
with the SIT regulator conversion kit. Using
a Torx T20 (with 1/4-in. shank and center
hole) or slotted screwdriver, remove and
discard the two pressure regulator mounting
screws, the pressure regulator tower, and the
diaphragm assembly (if applicable). Properly
dispose of all removed components. Make
sure the rubber gasket installed on the back
of the replacement pressure regulator is
properly positioned.
Step 7. Install the new stepper motor
pressure regulator assembly using the
supplied screws. Securely tighten the screws
(25 lb-in).
Step 8. Attach the enclosed identification
label to the valve body where it can be easily
seen.
Step 9. Make stepper motor and valve
electrical connections.
Step 10. Remove the pilot hood assembly to
access the hexed pilot orifice. Using a 5/32-
in. allen wrench, remove and replace the pilot
orifice with the one provided with the kit.
NOTE: Use extreme care to avoid
damaging the igniter assembly.
Step 11. Refer to Figure 57 and remove the
pilot hood assembly to access the hexed pilot
orifice. Remove and replace the orifice with
the one provided with the kit.
Step 12. (Refer to Figure 55 on Page 31 and
Figure 56)
VERIFY THE PROPER ORIFICE SIZE
BEFORE INSTALLING IT.
(from DFC Wire Harness)
Manifold (OUT) Test Port
Inlet (IN) Test Port
Wire
(from DFC Wire
Harness)
Main Gas Inlet
3/8" NPT
Figure 56
32
®
Figure 57
A. Remove the orifice from the manifold
and replace it with the one provided in
the kit. See the following table for orifice
sizes for natural and propane models.
Figure 58 illustrates the orifice. Use
pipe joint compound or Teflon tape on
all pipe fittings before installing (ensure
propane resistant compounds are used in
propane applications, do not use pipe joint
compounds on flare fittings).
B. Retrieve the burner and slide the venturi
tube over the orifice. Set the burner
assembly into its position and secure it.
C. Reinstall the grate assembly.
Step 13. Reassemble the remaining
components by reversing the procedures
outlined in the preceding steps.
Step 14. Attach the conversion label provided
in the conversion kit to the rating plate on the
appliance.
Step 15. Apply gas to the system and relight
appliance. With the main burner "ON", test
the new pressure regulator assembly and all
gas line joints for leaks using a gas leak test
solution. See Test All Connections For Gas Leaks
on Page 23.
Green Wire
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
DLX DIRECT VENT GAS FIREPLACES (MDLX40/45) • INSTALLATION INSTRUCTIONS
Pilot
Hood
Pilot
Orifice
Connect GTMS
wire harness.
Pressure Regulator
Tower
Yellow Ground Wire
(from DFC Wire Harness)
Burner Orifice Sizes
Elevation 0-4500 feet ( 0-1372 meters)
Model Natural Gas
drill size (inches)
MDLX40 0.1405 in. (#28)*
• H2286
MDLX45 0.161" (#20)*
• H2288
* Standard size installed at factory
• Part /Cat. Number
Table 14
Figure 58
Step 16. Relight the main burner and verify
proper burner ignition and operation. See
Burner Adjustments Pages 26 and 27.
Inspect the pilot system for proper flame. The
pilot flame should engulf the flame sensor as
shown in Figure 38 on Page 2.
The lighting instructions can be found on the
lighting label in the control compartment or
in the Care and Operation Manual provided
with the appliance.
Step 17. Using a manometer, test the inlet
and manifold gas pressures. See Tables 2
and 3 on Page 4.
ALWAYS TEST PRESSURES WITH THE
VALVE REGULATOR CONTROL AT THE
HIGHEST SETTING.
SEE PAGE 26 FOR AIR SHUTTER
ADJUSTMENT GUIDELINES.
Igniter Rod
Pilot Hood
Flame
Sensor
Figure 59
Propane
drill size (inches)
0.086 in. (#44)*
• H2287
0.093" (#42)*
• H4816
Pilot
Nozzles