Nordyne M4RC Upflow Installation Instructions Manual page 27

3. Measure / Adjust the Manifold Pressure:
The manifold pressure must be measured by installing a
pressure gauge (Manometer, Magnehelic Meter, etc.) to
the outlet end of the gas valve.
a. Remove the manifold pressure plug (Figure 35) from
the outlet side of the gas valve with a 3/16 Allen
wrench.
b. Install a 1/8 NPT fi tting, which is compatible with a
Manometer or similar pressure gauge.
c. Connect the manometer or pressure gauge to the
pipe thread fi tting.
d. Start the furnace by adjusting the thermostat 5
degrees above room temperature. Allow the furnace
to operate for 3 minutes.
e. Measure the manifold pressure on the manometer
or pressure gauge. Compare the measured value
to the value in Table 11 (page 41).
f. If the manifold pressure is not set to the pressure
specifi ed in Table 11, remove the pressure regulator
cap (Figure 35) from the gas valve. Slowly turn the
adjusting screw underneath the cap with a small
screwdriver until the appropriate manifold pressure
is obtained. NOTE: Turning the screw clockwise
increases the pressure, turning the screw counter-
clockwise decreases the pressure.
g. After the manifold pressure is properly set, replace
the cap so that the letters facing up represent the
type of gas being used for the furnace.
h. Adjust the thermostat to its lowest setting.
i. Turn off the main gas supply to the unit at the manual
shut-off valve, which is located outside of the unit.
j. Turn off all of the electrical power to the furnace.
k. Disconnect the manometer or pressure gauge.
l. Remove the 1/8 NPT fi tting and reinstall the manifold
pressure plug. NOTE: To prevent cross threading,
hand tighten the plug fi rst then tighten with 3/16
Allen wrench.
4. Complete the Conversion:
WARNING:
FIRE OR EXPLOSION HAZARD
Never test for gas leaks with an open fl ame.
Check all connections using a commercially
available soap solution. A fi re or explosion
may result causing property damage, personal
injury or loss of life. Failure to follow the safety
warnings exactly could result in serious injury,
death or property damage.
a. Turn the main gas supply valve (on the outside of
the furnace) to the ON position.
b. Check all gas connections for leaks with a soap and
water solution. If the solution bubbles there is a gas
leak which must be corrected.
c. Turn on all electrical power to the furnace.
d. Turn the gas valve ON/OFF knob (Figure 35) to the
ON position.
e. Start the furnace by adjusting the thermostat 5
degrees above room temperature.
f. Check the furnace for proper ignition and operating
sequence (See page 32).
g. After ignition, visually inspect the burner assembly
to verify that the fl ame is drawn directly into the
center of the heat exchanger tube.
In a properly adjusted burner assembly, the fl ame color
should be blue with some light yellow streaks near the
outer portions of the fl ame.
The ignitor may not ignite the gas until all of the air is bled
from the gas line. If the ignition control locks out, adjust
the thermostat to its lowest setting and wait one minute.
Adjust the thermostat 5 degrees above room temperature
and the ignitor will try again to ignite the main burners.
This process may have to be repeated several times
before the burners will ignite. Once the burners are lit,
check all gas connections for leaks again with the soap
and water solution.
WARNING:
Do not alter or remove the original rating plate
from the furnace.
h. Affi x the conversion warning label (P/N 703935)
to the outside of the unit door and the conversion
information label (P/N 703942) near the rating plate
inside the control area.
i. Affi x the gas conversion label from the conversion
kit on the gas valve. Each label should be prominent
and visible after installation.
j. Reinstall the appliance door.
k. Run the appliance through three complete cycles
to assure proper operation.
NOTES:
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