Lennox Merit Plus MPD35ST-NM-B Care And Operation Instructions Manual page 7

BTU Input
These fireplaces are designed as supplemental
heaters. Therefore, it is advisable to have an
alternate primary 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 Table 1.
Electronic Models - Electronic models have a
fixed rate gas valve. Input of electronic models
is shown in Table 1.
Input (BTU) Gas Valves (all models)
Models Fuel
Type
MPD35ST/PF-NM
Natural
(Millivolt)
MPD35ST/PF-PM
Propane
(Millivolt)
(if field converted)
MPD35ST/PF-NE
Natural
(Electronic)
MPD35ST/PF-PE
Propane
(Electronic)
(if field converted)
Table 1
Gas Pressure - All Models
Tables 2 and 3 show the appliances' inlet and
manifold gas pressure requirements:
Inlet Gas Supply Pressure
(all models)
Fuel # Minimum
4.5" WC
Natural Gas
(1.12 kPa)
11.0" WC
Propane
(2.74 kPa)
Table 2
Order Parts at: PartsFor.com or 866-607-2787
Manifold Gas Supply Pressure
Fuel #
Natural
Gas
Propane
Table 3
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 (refer to Figures 1 and 2).
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.
These appliances must be isolated from the
gas supply piping system (by closing their
individual manual shut-off valve) during any
Input Rate
pressure testing of the gas supply piping
(BTU / HR)
system at test pressures equal to or less
30,000 high
than 1/2 psig (3.5 kPa).
23,000 low
These appliances and their individual shut-off
28,000 high
valves must be disconnected from the gas
22,000 low
supply piping system during any pressure
testing of that system at pressures greater
than 1/2 psig (3.5 kPa).
30,000
These appliances must not be connected to a
28,000
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 4 ).
For elevations above 4500 feet, contact your gas
Maximum
supplier or qualified service technician.
10.5" WC
(2.61 kPa)
13.0" WC
(3.23 kPa)
NOTE: DIAGRAMS & ILLUSTRATIONS ARE NOT TO SCALE.
Order Parts at: PartsFor.com or 866-607-2787
(all models)
Low High
(Lo) 2.2" WC (Hi) 3.5" WC
(0.55 kPa) (0.87 kPa)
(Lo) 6.3" WC (Hi) 10.0" WC
(1.57 kPa) (2.49 kPa)
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 or by 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/CSA-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/CSA-B149.1 - latest edition.
Flame breadth, height and width will dimenish
4% for every 1,000 feet of altitude.
Burner Orifice Sizes (all models)
Natural
Elevation
Gas
Feet (meters)
drill size (inches) drill size (inches)
0-4500
*
#37 (0.104") 1.55 mm (0.061")
(0-1372)
24M10 •
Table 4 * Standard size installed at factory
• Part /Cat. Number
Burn-in Period
During the first few fires of 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.
A white film may develop on the glass front
during the first few fires as part of the curing
process. The glass should be kept clean during
the first two weeks of use to prevent the film from
baking on (making it very difficult to remove).
See Cleaning Glass on Page 10
Propane
Gas
*
42M79 •
7