Midco E20BP - Manual (Page 5)

-5-
AIR
VII MAIN GAS SPUD
Standard burners are approved for use with NATURAL or
PROPANE gas only, and should be used only with the gas
specified on the rating plate.
WARNING: The Model E20B is not suitable for con-
version to PROPANE gas. Using PROPANE gas in the
Model E20B may create a safety hazard and will void the
approval agency listings and the burner warranty. The
E20BP must be used for propane gas.
■ A standard E20B ECONOMITE (NATURAL) gas burner is
shipped with a .218 diameter orifice installed, the E20BP
ECONOMITE (PROPANE) a .180 diameter orifice installed for
an input capacity range of approximately 105 to 150 MBH
Spare spuds are included in a spare spud bag (stamped with
inch diameter) for other capacity ranges (see Table 3).
■ The combination valve pressure regulator is set to provide
2.0"W.C. manifold gas pressure for minimum spud input and
the blower air shutter is set for a maximum spud input, 32
turns from full closed, so as to provide a lean gas/air mixture
for initial start up.
■ If the required firing rate does not fall within the range of the
installed spud, select the correct capacity range from Table 3
and the spud with the correct orifice size (stamped with inch
diameter) from the spare spud bag. If the required firing rate is
at the minimum of a capacity range, select the next lower
range spud.
■ To change the main spud, turn off the Main Manual
Shut-Off Valve and burner power, remove the backplate,
disconnect the factory installed union located between the
combination valve and manifold slide plate and pull out the
curved manifold pipe. Unscrew the installed main spud from
the end of the curved manifold pipe and install the selected
main spud, making sure to reuse the fiber spud gasket.
Reassemble burner in reverse order.
WARNING: When reinstalling the curved manifold
pipe, make sure the manifold slide plate is positioned in
its holder and that the main spud is inserted into the end
of the nozzle. Refer to Figures 5 and 6. Reconnect union
and replace backplate.
*Main Gas Spud Orifice Size, approximate Manifold Pressure
and Air Shutter setting as shipped.
Data shown is approximate and based on ÒOÓ overfire pressure
at sea level.
TABLE 3 Main Gas Spud Capacity and
Preliminary Gas and Air Settings.
WARNING: Reposition the air shutter for the
maximum firing rate of the selected spud capacity range.
Do not change the combination gas valve pressure regulator
setting at this time.
CAUTION: The approximate air and gas settings
described above are for initial start up only. Final settings
must be made in accordance with Section VIII. Instructions
for adjustment of the manifold gas pressure are detailed in
Section XI.
VIII INITIAL START UP / ADJUSTMENT
1. Check the burner piping and valves for gas leaks by
applying a weak liquid soap solution to unions and joints
with the gas supply on. Leakage will be indicated by the
appearance of soap bubbles. Locate and correct all gas
leaks before proceeding.
WARNING: DO NOT USE OPEN FLAME.
2. Purging the air from the gas supply line at this step will
expedite the first light-off.
CAUTION: Purge outside the building. Do not
purge into the gas utilization equipmentÕs combustion
chamber.
3. To purge the heating appliance and chimney of any
accumulated gases, turn manual gas cock knob on the
combination valve to OFF, turn burner power on and set
the operating control to ON or thermostat to call for heat.
Let the blower run long enough to accomplish four air
changes but not less than five minutes.
4. CAUTION: Make sure that the capacity range of
the installed main spud and the air shutter setting
are suitable for capacity rating of the gas utilization
equipment. Refer to Section VII and Table 3.
5. Stop motor by setting operating control to OFF or
thermostat below room temperature.
6. Turn manual gas cock knob on the combination valve to
PILOT and depress completely, hold firm and light pilot by
depressing ignitor button several times. Pilot should light.
Pilot may be viewed through Peep Sight located in rating
plate (see Figure 5). Failure to light is probably due to air
in pilot gas line. Attempt several relights. Then, if
necessary, refer to Trouble Chart or Section IX to isolate
the problem.
WARNING: Repeated unsuccessful attempts to
light pilot will result in accumulated gases in gas
utilization equipment and chimney. To prevent
these gases from reaching an explosive level,
periodically purge the heating appliance and
chimney as described in Step 3 above.
FIGURE 5 Piping Connections