Cracked Boiler and Water Loss

jim_156

Explaining a cracked boiler and excessive make-up water

I need help on testing a theory that could be very usual to many out there.

I have been on the site before asking for advice on why the steam boiler system was losing so much water (650,000) BTU system, 10-15 gallons of make up daily. No amount of searching with ultrasound, infrared and a host of other tests ever found anything wrong with the pipes. And the amount was so large evidence of a major leak in the steam pipes or return pipes would have been evident. The one time we did replace a condensate pipe, the floor was steaming hot.

The loss startered shortly after the boiler was installed. Now after three years, the boiler cracked big time.

1)Here goes the theory: for a long time, there were one or more cracks where water leaked but vaporized and wentt up the flue. No water ever seen on the floor. Similar to taking a vent of a radiator and letting the steam pour out during every heating cycle.

2) I am not sure why it had such a big crack. Could the large amounts of feed water worsen the existing cracks or would simply be more likely that there big crack was the result of a defect in the cast iron from the beginning.

3) Note, there we no problems re Thermal Shock. Water is piped in through the condensate tank. Large amounts never would be added all at once, since there is not only a LWCO unit (ITT Series 81) but also the Series 150E, which calls for water well before the water lever ever reaches the lower water cut off level. All are working properly.

4) I am gearing up for a battle with the manufacturer when the cast iron block is dissembled and they look at the one or major cracks, together corrosion (e.g. pitting) from the oxygen in the make-up water.

My theory then, is that the crack caused major water loss, the cause pitting as lots of fresh water was added over the two years.

Does sound plausible? How much oxygen damage could have done. Would it have been able to cause the big crack by itself?

Jim

[Deleted User]

hmmm, interesting

because we had a similar problem with an evaporating, ghost leak, which was compounded by a known leak, which distracted us from seeing the ghost leak because they met at a common low spot on the floor

i took care of the known leak, clogged steam trap/vent, but it wasn't until the next day, when i found water on the floor again, that i could see that it wasn't coming from the vent, but coming from behind the side cover of the boiler. removed the soaked-insulation cover and bingo!; a crack. and even though it was below the water line/low crack, it only leaked when the boiler was firing. and sure enough, after the boiler made temp, the crack 'closed' enough to leave only a small leak that would evaporate before it made it to the floor

when it was disassembled, there were very large amounts of scale from about the water line down. and as much as 1/4" thick on the walls, to piles in the very bottom. we have excessive amounts of lime in our water, and the water treatment regime was changed