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False water line (5 Posts)
False water lineI have a customer with a boiler that continually goes off in low water. Smith boiler with powerflame burner. The near boiler is far from perfect, but has been there a long time and I believe this is a new problem. 2 risers with take off between.
Secondary lwco is installed in the equallizer in rear of boiler, well below the level in the feeder/primary control in the front of the boiler. Wet return T is above the water line. Original secondary (MM probe) appreared faulty, so I replaced with the required manual reset, I fired boiler and it made steam in 10 minutes and made pressure in 16.
Another no heat call. Boiler had plenty of water in glass, but lwco in reset. I reset the lwco and the burner fired. During initial few minutes, before making steam, water level in the glass went up and the boiler went into lwco condition indicating a "false waterline" condition. Once the boiler made steam, this seamed to settle down.
I remember reading about this in Dan's books, but can't remember cure and do not have access to my copies for a few days.
It sounds like PrimingClean the water side of the boiler. Surface skim the boiler until the crap on the surface is gone. That may help, but sell the customer on fixing the piping errors so the manufacturer will warrant their boiler. Do you have any photos of the piping? I know a boiler instructor, who would love them.
boiler piping photosThis boiler is actually not that bad, Take off between risers and equalizer T at wrong height. I have been seeing things lately that will send you off running, screaming into the night. I refer to it under the heading of "Hudson County piping". Attached is an example.
Lwco location-improper?Can the lwco be moved to a tapping on the boiler itself instead of the equalizer location?
This be easier than finding out why the waterline rises in the boiler, while at the same time falling in the equalizer. As Tim has said, there may be a dirty water condition, but why now suddenly?
The returns could have started to slow down with a blockage, thus preventing the water from returning as quickly as required to keep the minimum of water in the boiler. The improper supply risers may be shooting a lot of water up which then starves the lwco.
The false waterline was described by Dan as. a method of keeping high wet returns from being above the waterline of the new boiler.
What pressure is the boiler reaching?--NBCThis post was edited by an admin on March 28, 2013 3:44 AM.
False water lineThank you for your ideas. What is confusing me, is that I watched this happen during a cold start, before the risers got hot.
My use of term "false water line" may have been in error. I can picture in my mind the diagram where water would move to one end of the boiler. Maybe "slanted/tilted water line" is more accurate.
I am going there today to watch it fire again. I will update any finds.