16
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
LENNOX HEARTH PRODUCTS • MERIT
®
SERIES B-VENT GAS FIREPLACES • MODELS MLBV-35, MLBV-40 • INSTALLATION INSTRUCTIONS
Turn on gas supply and test for gas leaks, us-
ing a gas leak test solution (also referred to as
bubble leak solution).
Note: Using a soapy water solution is an
effective leak test solution but it is not recom-
mended, because the soap residue that is left
on the pipes/fittings can result in corrosion
over time.
A.
Light the appliance (refer to the lighting
instructions label in the control compartment
or in the Care and Operation Instructions
manual).
B.
Brush all joints and connections with the gas
leak test solution to check for leaks. If bubbles
are formed, or gas odor is detected, turn the
gas control knob (off/pilot/on) to the “OFF”
position. Either tighten or refasten the leaking
connection, then retest as described above.
C.
When the gas lines are tested and leak free,
be sure to rinse off the leak testing solution.
WARNING
Never use an open flame to
check for leaks.
Step 7. Verify Appliance
Operation
Turn on burner then observe the individual
tongues of flame on the burner. Make sure
all ports are open and producing flame evenly
across the burner. If any ports are blocked, or
partially blocked, clean out the ports.
With gas line installed run initial system check-
out before closing up the front of the unit. Follow
the pilot lighting instructions provided in the
Care and Operation Instructions manual. For
piezo igniter location, see Figure 17 (millivolt
appliances only).
Note: Lighting Instructions are also found on
the literature tag tied to the gas piping next
to the gas valve. To access the tag, open the
lower control compartment door by pulling
the panel forward (see Figures 17 and 25).
When first lighting the appliance, it will take a few
minutes for the line to purge itself of air. Once
purging is complete, the pilot and burner will
light and operate as indicated in the instruction
manual. Subsequent lighting of the appliance will
not require such purging. Inspect the pilot flame
(remove logs, if necessary, handling carefully).
Electronic Appliance Checkout
To light the burner, turn ‘ON’ the unit mounted
On/Off switch or the optional remote wall switch.
Ensure the igniter lights the pilot. The pilot
flame should engulf the flame rod as shown
in Figure 20.
MILLIVOLT
Thermocouple
Hood Igniter Rod
3/8" Min
(9 mm)
Thermopile
Pilot
Nozzels
Figure 19
Figure 20
ELECTRONIC
Pilot
Hood
Sensor
Igniter
Test All Connections for Gas Leaks
(factory and field)
Millivolt Appliance Checkout
The pilot flame should be steady, not lifting
or floating. Flame should be blue in color with
traces of orange at the outer edge.
The top 3/8" (10 mm) at the pilot generator
(thermopile) and the top 1/8" minimum (tip)
of the quick drop out thermocouple should be
engulfed in the pilot flame.
The flame should project 1" (25 mm) beyond
the hood at all three ports (see Figure 19).
Replace logs if removed for pilot inspection.
To light the burner; turn “ON” the remote wall
switch and rotate the gas valve control knob
counterclockwise to the “ON” position (“ON”
will be at the top side of the valve).
