Natural Gas - Lennox Hearth Products LMBV-36RMN Installation Instructions Manual

LENNOX HEARTH PRODUCTS • MERIT
Step 5. All Millivolt Systems – Attach ma-
nometer to the manifold side pressure test
fitting and verify manifold pressure reads
3.5" water column (0.87 kPa) for natural
gas, and 10.0" water column (2.49 kPa)
for propane gas.
Step 6. Refer to Figure 30 and remove the
pilot hood assembly to access the hexed pilot
orifice. Remove and replace the orifice with
the one provided with the kit.
electronic Appliances
Step 7. Honeywell electronic valves - See
Figure 32 and the instructions provided
with the kit. Remove the slotted cap screw,
o-ring, pressure-regulating adjusting screw
and spring. Retain all parts for possible later
use. Install new components from the kit.
Black cap and red spring for propane gas
units. Silver cap and stainless steel spring
fro natural gas units.
Before installing the cap, attach manometer
to the manifold side pressure test fitting and
adjust screw until pressure reads 3.5" water
column (0.87 kPa) for natural gas, and 10.0"
water column (2.49 kPa) for propane gas.
pilot
Orifice
Retaining
Flare Nut Clip
NOTE: If the igniter is damaged, a replacement
kit is available, order Catalog No. 87L54.
Figure 31
SERIES B-VENT GAS FIREPLACES • 36" LMBV MODELS • INSTALLATION INSTRUCTIONS
®
Manifold
Pressure
Test Port
Slotted
Cap
Figure 32
See Figure 31 and replace the pilot orifice as
follows: Remove the Igniter assembly retainer
clip, and carefully remove the igniter assembly.
Exercise extreme care to prevent damage to or
breakage of the Igniter assembly. Remove the
screw securing the pilot assembly to its mount-
ing bracket. Back off the flare nut at the end
of the pilot gas line to free the pilot assembly
from the gas line. Remove the pilot orifice
and replace it with the one provided with the
conversion kit. Reinstall the pilot assembly by
reversing the steps detailed here.
When reinstalling the igniter assembly,
use extreme care to prevent damage and
breakage. Do not apply any leverage to
pilot
the igniter assembly while restoring the
Assembly
retainer clip to its original position.
Igniter
Assembly
All models
Step 8. Unscrew the orifice from the manifold
and replace it with the one provided with the kit,
#42 (0.0935) for natural gas units and (0.058)
for propane (see Figure 33 ).
burner Orifice Sizes (all models)
elevation
Feet (meters)
0-4500
(0-1372)
Table 5
Figure 33
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Inlet Pressure Test Port
Spring
Adjusting
Screw
Natural propane
Gas Gas
drill size (inches) drill size (inches)
#42 (0.0935") * (0.058") *
H3721 • 67L28 •
* Standard size installed at factory
• Part /Cat. Number
Step 9. Reassemble all removed components
by reversing the procedures outlined in the
preceding steps. 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). Check for leaks
(refer to Page 11, Step 6).
Step 10. Attach appropriate conversion kit
label (see Figure 34) next to the rating plate
on the appliance.
THIS APPLIANCE HAS BEEN CONVERTED TO:

NATURAL GAS

INPUT BTU/HR – 24,000
MANIFOLD PRESSURE – 3.5"
ORIFICE SIZE – #42 (0.0935)
THIS APPLIANCE HAS BEEN CONVERTED TO:
PROPANE/LPG
INPUT BTU/HR – 24,000
MANIFOLD PRESSURE – 10"
ORIFICE SIZE – (0.058)
Figure 34
Step 11. Turn on gas supply and test for gas
leaks.
Step 12. Attach manometer to the manifold
side pressure test fitting and verify manifold
pressure reads 3.5" water column (0.87 kPa)
for natural gas, and 10.0" water column (2.49
kPa) for propane gas.
19