Surging Steam Boilers

MartinAssocHVAC

Hi all, this is my first post.  I have a serious problem and was told this is the place to go to get some help.  I'm going to give a quick overview of the system and what the issues are; hopefully someone out there had a similar issue and was able to get it fixed.  I work for Martin Associates in NY, we recently installed 2 gas fired steam boilers in a new residential building in NYC.  They are Weil Mclain 1088's with a vari-vac system.  Boilers are located on the 9th floor of a 37 story building; we have 2 steam outlets on each boiler, one on the top front near the LWC and one at the top rear near the safety valve.  Vacuum pumps, tank and condensate pumps are in the sub-cellar.  The steam supply comes out of the boiler header, and there is an express riser down to the 1st floor, where there is a steam supply loop.  We installed individual risers off of the main loop that feed up to the top of the building.  We boiled out both boilers twice already, flushed, cleaned, skimmed and everything else we could to try to stop the boiler surging (everyone we have spoken to says that we must have milling oil in the boilers).  Chemical tests revealed that the water is clean.  So to the heart of the problem......

We light the boiler off, the water level is at the correct level in the 157 cutoff / pump controller.  As soon as we start to make the slightest steam pressure, under about 50% firing rate, the water level in the sight glass shoots up to the top of the gauge glass and stays there.  We are getting lots of carryover, water hammer in the pipes etc.  As soon as we make pressure, the pressuretrol shuts the boiler down, and within 10 seconds of the flame going out the water level drops about 14 inches and is out of the sight glass,  the boiler goes off on low water.  By the time the boiler fills up again the pressure has dropped to about 2 psi and by the time the boiler lights off, the boiler pressure is actually in a vacuum.  I tried everything and nothing made any difference, except turning the fire rate down to minimum (we also don't make any steam at that rate) or closing the king valve.  As soon as i close the king valve, the boiler water level settles down and doesn't budge; even while lighting off a cold boiler at  0 psi.  It seems the system is causing the water in the boiler to get pulled up and out for some reason.  We eliminated it being a condensate return issue, we also eliminate contaminated boilers, and the boiler manufacturer said our piping arrangement was perfect.  The design engineer has no clue either........if anyone out there has any suggestions i am all ears....i have spent too nights and weekends there,  as well as thanksgiving in this building with the owner and the building super trying to keep the tenants warm....Please help!

ALIGA

can you post some pics

of the near boiler piping please.

MartinAssocHVAC

Take a look at the attachments...

I attached a copy of some pages out of the boiler manual, plus our draftsmans shop drawing and hartford loop detail.  It might be hard to follow, so let me know if you have any questions about routing, or pipe sizes.  I can get actual pictures tomorrow when i am on site....thanks again for your help

Anthony

nicholas bonham-carter

Pictures worth a thousand words-plans not so much

Pictures will be much easier to see, and Rembrandt that things are not always to plan. I don't see an equalizer on your elevation. What pressure is the boiler running at?--NBC

Unknown

the drawing

The drawing, something not right, when both boilers running, where do the wet steam goes before 'drying' out? Looks like they flow against each other and the equalziers on the side of the header???

MDNLansing

Balance

Could you post some pictures of the install please? If it installed like these plans so, you have nothing to balance and equalize the pressure in the boilers. Water is leaving one boiler and filling the other. You have allow both systems to balance and maintain equal pressure even if only one is running. It also doesn't look like there is any place for water in the header to go. Pictures of the install will help a lot.