Midco DS45B - Manual (Page 6)

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.
A standard Model DS45B ECONOMITE burner is shipped ready for NATURAL gas. As
shipped, it is field convertible to PROPANE gas. See Below.
A standard NATURAL gas Model DS45B burner is shipped with a .343 diameter orifice
installed for an input capacity range of approximately 225 to 320 MBH. A second orifice with
a .390 diameter orifice for an input capacity range of approximately 300 to 400 MBH is
included in NATURAL SPUD KIT attached to burner (see Table 3).
If a standard NATURAL gas Model DS45 is to be used with PROPANE gas, a conversion
kit which contains 5 main orifice spuds, a PROPANE regulator head, a PROPANE label and
instructions. Affix the PROPANE label over the NAT designation on the rating plate.
If the required firing rate does not fall within the range of the installed spud, or if convert-
ing to PROPANE gas, select the correct input capacity range from Table 3 and install the
spud with the correct orifice size (stamped with inch diameter) from the spud kit bag. If the
required firing rate is at the minimum of a capacity range, select the next lower range spud.
TO CHANGE MAIN SPUD: Turn Manual Gas Cock Knob on Combination Valve to OFF.
Remove the Spud Holder. See Table 3 and Figure 5 or 8.
The combination valve main gas pressure regulator is set to provide 2.0" W.C. NATURAL
(8.0" W.C. PROPANE) manifold gas pressure for low to minimum capacity spud input. The
burner is shipped with the primary air controlling shutter set wide open to provide a lean
gas/air mixture during the initial start-up. 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 .
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WARNING: Ignition is automatic. Make spark observations into combustion
chamber only with Main Manual Shut-Off Valve closed. Confirm that gas utilization
equipment does not contain any accumulated gases. Purge as described in Step 3
below.
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.
IMPORTANT: Purge outside the building.
Do not purge into the gas utilization equipment.
3. To purge the gas utilization equipment and chimney of any accumulated gases, turn
Manual Gas Cock Knob on Combination Valve to OFF, turn burner power on, and set
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.
VII Initial Start Up/
Adjustment
6
Part 1 Installation
Part 1
Installation
Continued
VII Main Gas Spud
Table 3: Spud Capacity and Preliminary Gas Settings