7
These appliances comply with National Safety
Standards and are tested and listed by ETL/
Intertek. (Report No. 100353019PRT-002) to
ANSI Z21.50 (in Canada, CSA 2.22), and CAN/
CGA-2.17-M91 in both USA and Canada, as
vented gas fireplaces.
Both millivolt and electronic versions of these
appliances may be used in bedrooms only
when the room is an “unconfined space” as
defined by the National Fuel Gas Code. Use in
bedrooms may not be allowed by your local
building codes. You should obtain prior approval
from the Authority Having Jurisdiction prior to
installation.
The installation must conform to local codes or,
in the absence of local codes, with the National
Fuel Gas Code, ANSI Z223.1/NFPA 54 - latest
edition (In Canada, the current CAN/CGA-B149.1
installation code).
The appliance, when installed, must be
electrically grounded and wired in accordance
with local codes or, in the absence of local codes,
with the National Electrical Code, ANSI/NFPA
70 - latest edition, or the Canadian Electrical
Code, CSA C22.1 - latest edition.
BTU Input
Millivolt and electronic models come standard
with a manually-modulated gas valve; flame
appearance and heat output can be controlled
at the gas valve. The BTU Input for these ap-
pliances are shown in
Table 1.
LENNOX HEARTH PRODUCTS • MERIT
®
SERIES DIRECT-VENT CONTEMPORARY DESIGN GAS FIREPLACES • MODEL MLDVTCD-35 • CARE AND OPERATION
Orifice Sizes
(Sea Level to High Altitude - All Models)
These appliances are tested and approved for
installation at elevations of 0-4500 feet (0-1372
meters) above sea level using the standard
burner orifice sizes (marked with an asterisk
[*] in
Table 4
). For elevations above 4500
feet, contact your gas supplier or qualified
service technician.
Deration
At higher elevations, the amount of BTU fuel
value delivered must be reduced by either:
• Using gas that has been derated by the gas
company.
• Changing the burner orifice to a smaller size
as regulated by the local authorities having
jurisdiction and by the (USA) National Fuel
Gas Code NFPA 54/ANSI Z223.1 - latest
edition or, in Canada, the CAN/CGA-B149.1
codes - latest edition.
Install the appliance according to the regulations
of the local authorities having jurisdiction and,
in the USA, the National Fuel Gas Code NFPA
54 / ANSI Z223.1 - latest edition or, in Canada,
the CAN/CGA-B149.1 - latest edition.
NOTE:
Flame appearance will diminish 4% per
thousand feet.
Test gauge connections are provided on the
front of the millivolt gas control valve, identi-
fied IN for the inlet and OUT for the manifold
side (see
Figure 3
and
Figure 4
on
Page 9
).
IMPORTANT NOTE!
A white film may develop on the glass
enclosure panel during the first few
fires as part of the burn-in process.
The first few times you use the
fireplace, clean the glass after
each use (
AFTER THE GLASS HAS
COMPLETELY COOLED
); otherwise,
the white film will bake onto the
glass and become difficult to
remove.
See “Cleaning Glass” on
Page 10
.
Input (BTU/HR) Manually Modulated
Gas Valves (all models)
Model
Input Rate (BTU / HR)
Nat. Gas
Prop. Gas
MLDVTCD-35
14,500 high
11,500 low
13,500 high
10,500 low
Table 1
Inlet Gas Supply Pressure
(all models)
Fuel #
Minimum
Maximum
Natural Gas
4.5" WC
(1.12 kPa)
10.5" WC
(2.61 kPa)
Propane
11.0" WC
(2.74 kPa)
13.0" WC
(3.23 kPa)
Table 2
Manifold Gas Supply Pressure
(all models)
Fuel #
Low
High
Natural
Gas
(Lo) 2.2" WC
(0.55 kPa)
(Hi) 3.5" WC
(0.87 kPa)
Propane
(Lo) 6.3" WC
(1.57 kPa)
(Hi) 10.0" WC
(2.49 kPa)
Table 3
Burner Orifice Sizes
Elevation 0-4500 feet ( 0-1372 meters)
Model
Series
Nat.Gas
drill size (inches)
Propane
drill size (inches)
MLDVTCD-35
#49 (0.073") *
21L82 •
0.045" **
75L10 •
*
Standard size installed at factory.
Table 4
•
Part /Cat. Number.
Gas Pressure Requirements
(All Models)
Gas pressure requirements are listed in
Tables 2 and 3
.
The appliance and its appliance main gas
valve must be disconnected from the gas
supply piping system during any pressure
testing of that system at test pressures
in
excess of 1/2 psi (3.5 kPa).
The appliance must be isolated from the gas
supply piping system by closing its equipment
shutoff valve during any pressure testing of
the gas supply piping system at test pressures
equal to or less than 1/2 psi (3.5 kPa).
In Canada - CAN/CGA-2.17-M91 (R2009)(high
altitude):
THE CONVERSION SHALL BE CARRIED OUT
BY A MANUFACTURER’S AUTHORIZED REP-
RESENTATIVE, IN ACCORDANCE WITH THE
REQUIREMENTS OF THE MANUFACTURER,
PROVINCIAL OR TERRITORIAL AUTHORITIES
HAVING JURISDICTION AND IN ACCORDANCE
WITH THE REQUIREMENTS OF THE CAN/CGA-
B149.1 OR CAN/CGA-B149.2 INSTALLATION
CODES.
Burn-in Period
During the first few fires in this appliance there
will be some odor due to the curing of the
paint and burning off of lubricants used in the
manufacturing process. Depending on your
use, the burn-in period may take a few hours
or a few days.
KEEP YOUR HOUSE WELL VENTILATED
DURING THE CURING PROCESS. THE ODOR
AND HAZE EMITTED DURING THE CURING
PROCESS CAN BE QUITE NOTICEABLE AND
MAY SET OFF A SMOKE DETECTOR.
If an optional blower is installed, do not turn it
on during the burn-in period.
