Junk in sight glass improving

Msil1955

Our installer recently spent another 3 hrs trying to clean our boiler. He installed a tee in the skim tap so he could look at the water as he skimmed it. He cleaned out the top and bottom of the sight glass plumbing and also the pigtail. He fashioned a wand and used some pressure, and said that quite a bit of stuff was dislodged with that method. The water was very clean, and the water level hovered at the halfway mark on the sight glass through a full heating cycle of 20 minutes. Not a sound anywhere in the system, and it was the first time the whole house didn't sound like it was sitting in a pot of boiling water. It was also the first time it did not go into low level shutdown from a cold start.
Less than 3 days later I heard a "snap" below the third radiator in the system, and now 2 weeks later it bangs loudly below that radiator when the steam reaches it. No noise from the Hartford loop. There are a few globs of oil on the sight glass, but still just a fraction of what we saw weeks ago.
I have a theory about this new noise, and would not have an inkling if not for the volumes of information I've gotten from this forum and excerpts from Dan's books. You guys are a wealth of knowledge.
The third radiator is a thirty foot run from the second one, and the steam pipe makes a 90 degree turn below it. That corner of the house has settled so that a three foot segment of the pipe is pitched in the wrong direction, allowing water to sit at that 90 turn. After the last skim session and the boiler was perfectly clean, the now clean and dry steam was able to heat up the pipes quickly. Prior to this there was so much carryover being drawn up into the system that it would heat the pipe from the bottom first, then the top of the pipe would get hot. At that point the system would go into low water shutdown with a lot of noise at the Hartford loop. When it restarted and finally made steam, the pipes and the water in them were preheated, so the standing water was not submitted to as much of a shock, and therefore no noise at the radiator.

As we now have some contamination visible, the steam is now not as dry, and deposits more water at the bend. With more water in the pipe at the bend, the steam hits it and vaporizes some of it, causing it to expand, and accelerating it down the pipe in a series of five or six waves. I can hear it moving like a shot from the 90 degree bend down to the next bend 30 feet away. The water level in the sight glass is now going from half, to full, then to about 1/2 inch, then to steady state at about 1/3. If we wait another week or so it will be sufficiently contaminated to shut the system down due to low water.
They're coming back to skim again. They wanted the Weil Mclean rep to come with them, but I knew he wouldn't. They obviously got some pointers from him, and are making an honest effort to fix the problem. It's a learning experience for all of us. I just wish they were the experts they claimed to be when quoting the job.

STEVEusaPA

You should keep this all in the same thread, instead of starting another.

ethicalpaul

I like your theories about your system. It's interesting they wanted the WM rep to come with them...all the information they needed is in the WM boiler instructions.

Hap_Hazzard

Here's a link to the previous thread. https://forum.heatinghelp.com/discussion/178028/junk-in-sight-glass

EBEBRATT-Ed

@Msil1955

If you have a pipe pitched the wrong way....get it fixed. If it's pitched the wrong way you will always have problems...that has nothing to do with the boiler or the skimming


Completely normal to need to be skimmed more than once

Msil1955

Understood. But I can't figure out why it's a problem now. The last boiler lasted 33 yrs with no noise in that area. But I'll definitely get it fixed. Thank you.

Fred

Msil1955 said:

Understood. But I can't figure out why it's a problem now. The last boiler lasted 33 yrs with no noise in that area. But I'll definitely get it fixed. Thank you.

There is a "tipping point" where a marginal pitch might work but if enough settling occurs or if the pipe gets jostled enough, say in a new boiler installation or other pipe work, it no longer works.

EBEBRATT-Ed

@Msil1955

It's just Murphy's law. You touch a system and everything else that was not a problem becomes a problem. Maybe the new boiler steams a little faster

Msil1955

It definitely steams faster