UVG-300

Common issues

• Soot fire due to excessive soot accumulation
• Tube fin damage (erosion, corrosion, or mechanical)
• Condensation corrosion, especially in low-temperature zones or during low-load operation
• Tube leaks (water/steam side) from corrosion or thermal stress
• Exhaust gas side fouling reducing heat transfer efficiency
• Malfunction or improper setting of safety valves
• Water-side scaling or sludge accumulation (if water-tube type)

Inspection checklist

• Inspect gas passages and tube surfaces for soot accumulation and signs of soot fire (e.g., discolored paint, distorted casing).
• Examine tube fins for erosion, corrosion, mechanical damage, or missing sections. Pay close attention to gas entry points.
• Check for signs of condensation corrosion, particularly at the cold end, gas outlet, and drain points. Look for pitting or thinning.
• Verify the functionality and condition of soot blowers (if fitted), including nozzles, lances, and steam/air supply lines.
• Conduct a thorough external visual inspection for any signs of water/steam leaks from tubes, headers, or flanges.
• Confirm safety valve test dates and verify their general condition. Check for signs of leakage or tampering.
• Inspect the integrity of the casing, insulation, and refractory lining (if present) for cracks, damage, or hot spots.
• Verify the proper operation and clear condition of all drain lines and collection tanks.
• Check instrumentation (pressure gauges, thermometers, level indicators) for accuracy and proper function.

Service intervals

Typical wear limits

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

Critical spares

• Soot blower nozzles and lances (if fitted)
• Safety valve overhaul kits (springs, discs, seats) or complete spare safety valve
• Assorted gaskets and packing for access doors, manholes, and flanges
• Tube plugging tools and a selection of tube plugs for emergency repairs
• Refractory repair compound (if applicable to design)
• Spare pressure gauges and temperature sensors for critical points
• Water level gauge glass and cocks (if applicable)

Safety

• Soot fire: Risk of uncontrolled combustion, leading to tube rupture, casing damage, or fire spread.
• High-pressure steam/water release: From tube rupture or safety valve malfunction, causing severe burn hazards.
• Hot surfaces and exhaust gases: Risk of burns during inspection or maintenance.
• Confined space entry: During internal inspections, requiring strict permit-to-work procedures and gas monitoring.
• Potential for exhaust gas leakage: Into machinery spaces, posing asphyxiation or toxic gas risks.

Class survey

Class surveyors will typically focus on the integrity of the pressure boundary. This includes internal gas-side inspection for tube integrity, corrosion, erosion, and soot build-up. Verification of safety valve functionality, lifting pressure, and certification is paramount. An external inspection for leaks, casing integrity, and insulation condition will be conducted. Review of operational logs and maintenance records, especially regarding soot blowing, water treatment, and previous repairs, is crucial. Thickness measurements of pressure parts (tubes, headers) will be performed as deemed necessary, particularly in areas prone to corrosion or erosion. Confirmation of proper drainage arrangements and alarm functions will also be checked.