Lennox Hearth Figure 55 Millivolt Appliances, Figure 56, Figure 57, Figure 59

38
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Figure 55
Millivolt Appliances
Step 5. SIT Systems - Refer to Figure 55 and
the instructions provided with the kit. Using
a Torx T20 (with 1/4" shank and center hole),
tool or standard flat screwdriver remove and
discard the three pressure regulator mounting
screws. Remove the pressure regulator, spring,
poppet, diaphragm and bushing. Discard all
removed components.
Ensure the rubber gasket installed on the back of
the replacement pressure regulator is properly
positioned and install the new pressure regula-
tor using the new screws supplied with the kit.
Tighten screws to 25 In. lb. torque.
Electronic Appliances
Step 7. Dexen Electronic Valves - See Figure
58 and the instructions provided with the
kit. Remove and discard the two pressure
regulator mounting screws. Remove the
pressure regulator and diaphragm. Discard
all removed components. Ensure the provided
diaphragm is installed properly onto the
replacement pressure regulator and install
the new pressure regulator using the new
screws supplied with the kit. Tighten screws.
Step 6. See 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.
Figure 56
Figure 57
Pressure
Regulator
Remove
These
Components
Pilot
Orifice Figure 58 - Dexen Electronic Gas Valve
Supply Gas
Inlet
Pressure-Tap
(Manifold)
Regulator
Mounting
Screw
Burner Stage
Terminal Gas
Outlet
To Burner
Ground (TP)
Pilot Stage
Terminal
Pilot Gas Outlet
Pressure-Tap
(Inlet)
PILOT
OUT
VENT
LO
TH TP
TH
TP
HI
IN
IN
LENNOX HEARTH PRODUCTS • MERIT® SERIES DIRECT-VENT GAS FIREPLACES • MODELS MLDVT-30/35/40/45 • INSTALLATION INSTRUCTIONS
Burner Assembly
Gas Valve
Assembly
Orifice
Note: If the igniter is damaged, a replacement
kit is available, order Catalog Number 87L54.
Figure 59
ELECTRONIC
Pilot
Hood
Sensor
Igniter