Low Water Autofeed Overfilling Boiler

I have a Utica (peg112cde) gas fired steam boiler that has a McDonnell uni-match (wf2-u-24) low water autofeed (better safe than sorry w/tenants). The low water shutoff is also made by McDonnell (ps-805 u-24). My issue is that when the boiler's water level goes down after around 30 or so heat cycles due to normal radiator steam release, the water level is sufficiantly low enough to trigger the autofeed but it overfills the boiler, ie, the water in the sight glass is all the way up & just into the valve on top when the steam condenses back into water. I've looked for some sort of adjustment but can't seem to locate one on either the autofeed or the low water shutoff. This can't be normal (it fills the boiler way above the recommended max water level sticker behind the sight glass). Any suggestions? Thanks, DAS

 

Is this a new install? Was the boiler properly skimmed of impurities?
I ask that because many times if water impurities(within the boiler) are present, steam trying to break the surface tension can cause the water to roll to one side within making the lwco "think" it needs water.
If the WL bounces profusely(and it only will while firing), and/or is quite dirty, I would most certainly skim-it again!

 

I was having a lot of problems w/the boiler initially but I had a boiler guy come & take a look at it. It was a new install in 2004 & he came in December, 2005. Amoungst other repairs I believe he did skim it. I have a question though. What's involved w/skiming a steam boiler? I'm curious 'cuz it sounds like something I should know how to do. Thanks, DAS

 

Well, every steam boiler manufacturer has their-own skimming instructions and "believe you me" it takes awhile! If the proper tappings have been set-up for this, I have never successfully skimmed one(new) in less than 4-6 hrs.
Read your owners manual again and again.
If your steam guy did it in less, I would question the impurities left behind!
Hope this helps.