Aalborg-OS-TCi-4.0-7bar

Common issues

• Soot and scale buildup on smoke-side heating surfaces reducing efficiency and raising exhaust gas temperature
• Refractory cracking around the furnace/burner throat from thermal cycling
• Burner flame instability or poor atomization from a worn nozzle or fuel viscosity out of range
• Water-side scaling and pitting corrosion from poor feedwater treatment
• Safety valve seat leakage or set-pressure drift over time
• Feed pump or feedwater regulator wear leading to level control problems
• Furnace or tube plate cracking from repeated thermal shock at low-load operation

Inspection checklist

• Internal inspection of furnace, smoke tubes and tube plates for pitting, scaling and cracking
• Check refractory condition at the furnace mouth and burner throat
• Function test safety valves (lift and reseat) at rated set pressure
• Check water level gauge glasses, alarms and low-water cutout function
• Verify burner flame pattern, atomization and combustion air/fuel ratio
• Check soot blower operation and coverage of heating surfaces
• Inspect feed check valve, non-return valve and feedwater regulator
• Check boiler mountings (main steam stop, blowdown valves) for tightness
• Test high/low water alarms and any remote monitoring signals
• Review boiler water treatment chemistry (TDS, pH, chlorides, alkalinity)

Service intervals

Typical intervals for this design class, not the manufacturer’s figures for your model. The manufacturer’s manual is binding.

Typical wear limits

Ranges are typical for this design class. Always confirm against the manufacturer documentation for your serial number.

Critical spares

• Burner nozzle/atomizer assembly
• Safety valve spares (springs, seats) sized for the 7 bar design pressure
• Water level gauge glass set and gaskets
• Feed check/non-return valve
• Ignition electrodes and flame scanner (photocell/UV)
• Refractory repair material for the furnace throat
• Feedwater regulator (level control) spares
• Manhole/handhole door gaskets

Safety

• Low-water condition risk of pressure part failure or explosion if level alarms/cutouts are untested or defeated
• Hot surface contact burns from uninsulated steam lines and boiler shell
• Steam/hot water release from blowdown valves during operation
• Furnace explosion (puff-back) from unburned fuel accumulation after a failed ignition attempt
• Pressure part failure risk from operating with scaled or uninspected heating surfaces

Class survey

Auxiliary boilers normally fall under Continuous Survey Machinery (CSM) or a fixed special-survey internal/external examination, depending on the vessel's survey scheme. Surveyors expect current safety valve test records, water treatment logs, and internal inspection reports showing no unaddressed pitting or cracking on pressure parts.

Estimated lifetime: Marine oil-fired auxiliary boilers of this size class are typically designed for 20-25+ years of service given proper water treatment and periodic internal surveys; pressure part life is governed by class renewal surveys rather than a single fixed hour figure.