16)Set the flue collector onto the block and press down so that the flue collector is set into the silicone applied in the previous step.
17)Slide the flue collector lugs back into position and retighten the
18)Apply a bead of silicone around the outside of the joint between the heat exchanger and the flue collector.
19)Reattach all the jacket components.
20)Reconnect the pressure switch tubes (see Figure 46 for correct tubing orientation).
21)Reconnect the fan.
22)Reconnect the vent system.
23)Reinstall the burner tray.
Service Notes
1) Orifice Size – Sea level orifice sizes are:
Natural Gas – #50 Drill Size
LP Gas – Consult Factory
Consult your Crown representative for correct orifice sizes for use at altitudes above 2000 ft. Orifice for this boiler cannot be drilled in the field.
2)Operating the Boiler with Intake Cover Removed – For inspection and troubleshooting purposes, this boiler may be started and run with the intake cover removed. When this is done, a resonance (“hum”) may be observed. This is normal and should disappear as soon as the intake cover is replaced.
WARNING
Do not leave the boiler in service with the intake cover removed.
3)Pressure Switch – This boiler is equipped with a differential pressure switch which makes when there is adequate flue gas flow through the boiler. This switch measures the pressure drop across an orifice plate inside the flue collector - the higher the flue gas flow through this plate, the higher the pressure drop. The N.O. contacts on the pressure switch make, allowing the boiler to fire, when the pressure drop across the flue collector orifice plate switch exceeds the “make setting” shown in Table 7. Once the switch is made, the boiler will fire as long as the pressure at the switch is above the “break setting” shown in Table 7. The pressure at both pressure switch tappings is actually below atmospheric (“negative”) with the pressure at the upper flue collector tap being the more negative of the two pressures. Figure 46a shows the pressure switch connections.
Figure 46b shows the correct method of reading the pressure across the pressure switch tappings. It is normal for the pressure reading across the switch to drop as the boiler heats up.
4)Burner and Pilot Removal - If necessary, the pilot can be removed without removing the burner tray. To do so, remove the screws holding the main burners on each side of the pilot bracket. The main burners will then be loose enough to allow the pilot hood to slip between them.
Main burners cannot be removed without removing the burner tray from the boiler.
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