Nordyne M1GH 056 Installation Instructions And Owner's Manuals page 19

COMBUSTION AIR
In order for the flame to burn efficiently, it must receive
adequate combustion air. The amount of combustion air
required will vary depending on altitude, actual B.T.U. content
of the fuel being used, gas pressure, conversion to another
gas and other factors. The burner flame should be observed
and any necessary adjustments made before the furnace is
placed into service. See Table 9 for Factory Air settings.
Gas Gun
Combustion air adjustment is made to the main burner
by loosening the lock nut on the plastic air shutter,
located on the side of the plastic burner air inlet box.
Move the threaded rod to a smaller number (counter-
clockwise) for less air, to a larger number (clockwise)
for more air. Tighten the lock nut after completing the
adjustment. For best results, use instruments to mea-
sure between 8-9% CO 2 after the combustion air has
been adjusted.
Oil Gun Only
It is recommended that the CO 2 and Smoke levels
should be measured for maximum performance. CO 2
readings should be 10-11% for 66,000 BTUH furnaces
and 12-13% for 86,000 BTUH furnaces. The Smoke
should be N0. 0 on the Bacharach Scale, and 0 to 0.02
negative draft over fire.
Electrode Setting (Oil Gun Only)
Poor ignition of the oil spray may result if the elec-
trodes are not adjusted as shown in Figure 32. Do not
permit any electrodes to be grounded to any surface.
GAS CONVERSION
This gas fired heating appliance was shipped from the factory
for use with natural gas. However, the appliance can be
converted for use with LP gas. Use the following procedure
for gas conversion of the burner.
ATMOSPHERIC AND DIRECT IGNITION FURNACES
a. Follow the instructions to "Turn Off Gas to the Appliance."
b. Disconnect the gas pipe union and the electrical wires
connected to the gas valve.
CAUTION:
!
• Combustion air adjustment must be made only
by a qualified technician. Improper air
adjustment may cause unsafe operation,
explosion and/or fire asphyxiation.
• If the input to the furnace is too great because
of excessive gas pressure, wrong size nozzle
or orifice, high altitude, etc., the burner flame
will be sooty and can produce carbon
monoxide, which could result in unsafe
operation, explosion
asphyxiation.
and/or fire or
Factory Combustion Air Settings
M1B* - 066 = 2.5
M1B* - 086 = 3.75
M1S* - 066 = 3.0
M1S* - 086 = 5.0
5/16" ABOVE CL
1 3/8"
Figure 32. Oil Gun electrode Position
c. Remove the pilot tube and thermocouple from the gas
valve (M1G*).
d. To remove the gas valve assembly, remove screw(s)
from gas valve bracket. Gas valve and spud may be
removed. Orifice is located at the end of the spud
(M1G*,M1M*),or remove three (3) bolts from U-shaped
manifold plate and orifice assembly (M1B*).
e. Replace the main orifice with the L.P. gas orifice supplied
in the envelope located by the gas valve. Check to insure
the orifice size matches the nameplate.
f. It is not necessary to convert the pilot orifice.
g. For Honeywell gas valves with the regulator converter
(Figure 33), check for the letters NAT or LP on the
pressure regulator cap. Unscrew the cap, invert it, replace,
and tighten until snug.
h. For the Robertshaw gas valve with the regulator converter
(Figure 34), remove the black cover and unscrew the
converter located on top of the gas valve. Invert the
converter. (For "LP" the red ring will be located at the
bottom and the "LP" stamping on the converter will appear
right side up.) Then screw converter back into the regulator,
hand tight plus 1/8 turn, and replace the black cover onto
the converter top to protect the threads.
i. Reassemble the burner assembly into the furnace.
j. Reconnect the gas piping and electrical wires to the gas
valve.
Table 9.
5/32" GAP
ELECTRODE
NOZZLE
0-1/16"
19