Leakage of treated boiler water (through a leaking blowdown pipe, valve, water tube, or circulating pump) and excessive blowdown both lead to a loss of treated water. Replacing this lost water with untreated makeup water dilutes the TDS and chemical reserves.

Action:

• Inspect all boiler blowdown pipes and valves for leaks and repair as necessary.
• Check for leaks in water tubes (indicated by white smoke from the funnel). Repair any leaks found.
• Inspect circulating pumps for leaks and repair as necessary.
• Once leaks are repaired, add chemicals to restore the desired levels.
• Monitor boiler water conditions through frequent testing.

(ii) Reduction in phosphate reserve, with an increase in chlorides and total dissolved solids:

Seawater ingress is the likely culprit. Seawater contamination introduces carbonates, sulfates, and chlorides of sodium, calcium, and magnesium. These ions react with phosphate in the boiler, forming non-scale sludge, leading to reduced phosphate reserves and increased chlorides and TDS.

Action:

• Identify and plug any leaky condenser tubes causing seawater ingress.
• Inspect and replace sacrificial anodes if necessary. This helps prevent corrosion.
• Increase the frequency and duration of boiler water blowdown.
• If chloride levels remain high, reduce boiler load to 2/3 normal output, blow down to minimum level, and refill with fresh make-up water.
• A complete emptying and flushing of the boiler is the ultimate solution to remove the remaining contamination. Carry out this at the earliest opportunity.

(iii) Reduction in alkalinity reserve only:

• Seawater contamination potentially introduces acidic products that neutralize the alkaline reserve.
• Boiler water leakage (loss of alkaline water).
• Oil contamination (oil can react to reduce alkalinity).
• Ingress of air (air can lead to the formation of acidic products that neutralize alkalinity).

Actions:

• Identify and rectify any seawater ingress.
• Maintain a high hotwell temperature to prevent air ingress.
• Identify and repair any boiler water leaks.
• Identify and eliminate the source of oil contamination.

(iv) Increase in oxygen levels only:

• Poor performance of the de-aerator, allowing oxygen to remain in the feedwater.
• Insufficient hydrazine reserves (hydrazine is an oxygen scavenger).
• Low hotwell temperature (oxygen is more soluble in colder water).
• Leaking feed water pump gland (allowing air to enter).

Actions:

• Inspect and repair any faults in the deaerator.
• Ensure adequate hydrazine reserves are maintained.
• Maintain a high hotwell temperature.
• Identify and repair any gland seal leaks in the feed water pump.

• Complete data allows for the identification of subtle trends indicating developing problems. A gradual decrease in alkalinity, for example, might not immediately exceed the alarm threshold but could signal a developing issue that can be addressed proactively.
• Comparing current results to past results helps establish a baseline and allows for easier detection of anomalies.
• Complete data provides more context during troubleshooting. If a problem arises, having access to a complete history can help identify the root cause more effectively.
• Logged data enables proactive adjustments and repairs before faults escalate, preventing boiler damage and reducing unplanned downtime.