erratic water level

Stan_5

I installed a 150,000 btu input steam boiler 10 years ago. The customer recently developed a severe steam leak in the crawlspace which resulted in major mold growth and buckled their hardwood floors above. The steam pipe was replaced and the wet return also. Now they are getting water hammer in the short, horizontal return pipe between the return tapping of the boiler and the hartford loop tee. When the boiler starts to heat, the water line rises above the top of the sight glass. We lowered the water level enough so we could watch it. Water is spilling in the top of the sight glass and I could see dirt particles flowing down the sight glass and into the boiler through the bottom of the sight glass. We opened the return of the boiler and saw alot of metal flakes but no real accumulation of mud. We skimmed the boiler but that did'nt help. The customer said they did'nt have any water hammer problems for the last 10 years. I'm wondering if it has something to do with the amount of make-up water the boiler saw because of the steam leak. Any information would be appreciated.

Norm Harvey

Got any pictures?

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Stan_5

Sorry, I don't have any.

Brad White

No pictures but you sure got music....

What I would first check is the "A" dimension, the dimension from the boiler waterline to the lowest steam carrying pipe. Was it maintained at at least 28 inches? Is the boiler operating on the lowest possible pressure which will do the job?

The second thing is in your text (maybe should have been the first thing). You mentioned the "short horizontal return pipe between the boiler tapping and the Hartford loop tee". I am not clear on this but am hoping that the Hartford loop connection to the equalizer is a close-nipple with no length to speak of. No chance for a rush of velocity as steam and condensate battle it out in the equalizer.

Was the entirety of the near-boiler piping done per the manufacturer's instructions, explicitly?

Stan_5

It was quite frightening!

I'm positive the "A" dimension is at least 28" and the near boiler piping is as per manufacturers instructions. The Hartford loop connection to the equalizer is definitely a close nipple. The water hammer occurs somewhere between the tee where the Hartford loop connects to the equalizer and where the condensate enters the boiler. The operating pressure is also at the lowest setting. At first we thought something was plugged inside the boiler but the only thing I can come up with is possibly severe erosion inside the boiler from the amount of make-up water the boiler went through because of the steam leak. The customer did mention they never had water hammer for the past 10 years which is how old the boiler is. The only thing that changed is the development of the steam leak which we fixed.