3
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Inlet Gas Supply Pressure
(all models)
Fuel #
Minimum
Maximum
Natural Gas
4.5" WC
(.2 kPa)
0.5" WC
(2.6 kPa)
Propane
.0" WC
(2.74 kPa)
3.0" WC
(3.23 kPa)
Table 3
Gas Pressure - All Models
Tables 3 and 4
show the appliances' gas
pressure requirements:
Test gauge connections are provided on the
front of the millivolt and electronic gas control
valve (identified IN for the inlet and OUT for
the manifold side). The control valves have a
3/8" (10mm) NPT thread inlet and outlet side
of the valve.
Gas Valve Diagrams
See
Figure 1
for Millivolt models and
Figure 2
For Electronic Models.
These appliances must not be connected to a
chimney or flue serving a separate solid fuel
burning appliance.
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 "*" in
Table 5
). For elevations above 4500 feet,
contact your gas supplier or qualified service
technician .
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/CSA-B149.1 - latest edition.
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
(.57 kPa)
(Hi) 0.0" WC
(2.49 kPa)
Table 4
Burner Orifice Sizes
Elevation 0-4500 feet ( 0-372 meters)
Model
Series
Nat.Gas
drill size (inches)
Propane
drill size (inches)
MLDVT-30
#50 (0.070")*
H4873•
#59 (0.04")*
H7838
MLDVT-35
#49 (0.073")*
2L82•
0.045"*
75L0•
MLDVT-40
#43 (0.089")*
99K75•
#55 (0.052")*
9L52•
MLDVT-45
0.090"*
37L70•
#54 (0.055")*
99K79•
Table 5
These appliances must be isolated from the
gas supply piping system (
by closing their
individual manual shut-off valve
) during any
pressure testing of the gas supply piping
system at test pressures equal to or
less
than
1/2 psig (3.5 kPa).
These appliances and their individual
shut-off valves
must be disconnected
from
the gas supply piping system during any
pressure testing of that system at pressures
greater than
1/2 psig (3.5 kPa)
.
Propane tanks are at pressures that will cause
damage to valve components. Verify that the
tanks have step down regulators to reduce the
pressure to safe levels.
Do not use these appliances if any part has been
under water. Immediately call a qualified, profes-
sional service technician to inspect the appliance
and to replace any parts of the control system and
any gas control which have been under water.
Ne pas se servir de cet appareil s'il a été plongé
dans l'eau, complètement ou en partie. Appeler
un technicien qualifié pour inspecter l'appareil et
remplacer toute partie du système de contrôle et
toute commande qui ont été plongés dans l'leau.
SIT Millivolt Gas Valve
Figure 1
Input (BTU) Manually-Modulated
Gas Valves (all models)
NATURAL GAS
Models
Input Rate (BTU / HR)
MLDVT-30N
3,500 high
0,500 low
MLDVT-35N
6,000 high
2,500 low
MLDVT-40N
22,000 high
7,000 low
MLDVT-45N
23,000 high
7,500 low
Table 1
Input (BTU) Manually-Modulated
Gas Valves (all models)
PROPANE GAS
Models
Input Rate (BTU / HR)
MLDVT-30P
2,500 high
9,000 low
MLDVT-35P
5,000 high
,500 low
MLDVT-40P
20,000 high
5,800 low
MLDVT-45P
22,000 high
7,000 low
Table 2
Provide adequate clearances around air open-
ings and adequate accessibility clearance for
service and proper operation. Never obstruct
the front openings of the appliance.
These appliances are designed to operate on
natural or propane gas only. The use of other
fuels or combination of fuels will degrade
the performance of this system and may be
dangerous.
These fireplaces are designed as supplemental
heaters. Therefore, it is advisable to have an alter-
nate heat source when installed in a dwelling.
Millivolt Models -
The millivolt appliances are
manually controlled and feature a spark igniter
(piezo) that allows the appliance's pilot gas to
be lit without the use of matches or batteries.
This system provides continued service in the
event of a power outage.
Millivolt models come standard with a manu-
ally-modulated gas valve; flame appearance and
heat output can be controlled at the gas valve.
The BTU Input for these appliances is shown
in
Tables 1 and 2.
H I
LO
W
HT
PT
HT
PT
PILO
T
PI
LO
T
ON
it
OFF
IN
OUT
Manifold Pressure Tap
Inlet Pressure Tap
Pilot Adjustment
Screw
HI/LO Variable
Flame Height
Adjustment
Main Gas Control Knob
OFF/PILOT/ON
* Standard size installed at factory
• Part /Cat. Number
Summary of Contents for Merit MLDVT-45NE
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