How to check boiler tube leakage and tube plugging

1. In case of tube failure, steam pressure has to be removed and the oil burner dismantled.
2. If the leakage is readily visible from the burner hole, the boiler can be emptied and repairs commence.
3. Otherwise, the boiler is given pressure by means of the feed pump. The position of the leakage will be indicated by the water flow.
4. This flow may not be visible from the burner hole. If it is not visible, remove the inspection door and enter the furnace. If the tube failure is still not found, then enter the generating tube section. From here the bottom of the membrane walls and generating tubes can be inspected for leakage.
5. If the leakage has resulted from the membrane walls or generating tube, the inspection door at the smoke connection pipe must be removed, and the generating tube/ membrane tube in which the failure has occurred is pointed out.
6. The leakage may also result from economizer.
7. By removing the inspection door at the bottom of the economizer, it can be determined which uptake has caused the leakage.
8. If necessary other inspection doors should be removed to point out the damage register.
9. When a damaged tube or convection register has been removed, and the remaining tube studs have been repaired/ plugged a new tube or register should be mounted as soon as possible.
10. Operation for longer periods with one or more registers missing involves the risk of further damage to the boiler due to increasing heat leads on the parts next to the ones removed.
11. Remove any scale from the end of the tube with a wire brush making certain it is clean, round and smooth so there’s a good metal to metal fit between the machined steel plugs and tube.
12. Gently tap the plug into the tube (both ends), the water pressure will hold it and hammering excessively can distort the drum or header.
13. Refill boiler and check for leaks before start-up.
14. Start up boiler and check for leaks when pressurized.

quote: https://www.brighthubengineering.com/marine-engines-machinery/77555-repairs-in-marine-boilers/