Crown Boiler MWC116ENL - Manual (Page 66)

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Figure 14.2: Inducer
Neg. Pressure Tap
Venturi
WARNING
Do not leave the boiler in service with the Inner Cover removed. •
Do not attempt to fi re this boiler with the Combustion Chamber Cover (Fig. 14.1) removed •
Service Notes
Orifi ce Size 1) – Sea level orifi ce sizes are:
Natural Gas – 1.30 mm
LP Gas – 0.85 mm
Consult your Crown representative for correct orifi ce sizes for use at altitudes above 2000 ft. Orifi ce for this boiler
cannot be drilled in the fi eld.
Operating the Boiler with Inner Cover Removed 2) – For inspection and troubleshooting purposes, this boiler may
be started and run with the Inner Cover (Figure 12.5) removed.
Pressure Switch 3) – If necessary, the air pressure switch signal may be read using a slant tube or electronic
monometer connected across the taps on top of the boiler (Figure 14.4). The N.O. contacts on the pressure
switch make, allowing the boiler to fi re, when the switch signal exceeds the “make setting” shown below. Once
the switch is made, the boiler will fi re as long as the pressure at the switch is above the “break setting” shown
below. It is normal for the pressure reading across the switch to drop as the boiler heats up.
Make Setting - 0.64 w.c.
Break Setting - 0.59 w.c.
Limit Reset Buttons 4) - Manual reset buttons for the fl ue temperature and supply water limits are located on the
top of the boiler as shown in Figure 14.4. To access the buttons, unscrew the plastic covers.