Boiler Skimming, need wisdom!

Crich199

Have been installing and servicing steam boilers for about 6 years now. In the beginning of my install career my company used Weil McLain steam boilers and after installing per the manufacturer’s instructions for near-boiler piping and the initial skim to remove any sediment/manufacturing oils, we rarely had issues with surging and water hammer. About 2 years ago we switched over to installing Utica brand boilers. It seems even though after strictly following the manufacturer’s instructions for near boiler piping and dimensions and the same initial skim, we have been having a ton of issues with these boilers surging and causing water hammer. We are very careful to properly support all existing steam piping before replacement of the old boiler, so pitch on the existing piping is the same and is not manipulated by the new near boiler piping so I can’t imagine that is the issue since many homeowners state they never had surging or water hammer prior to install of the new Uticas. After returning to many of the boilers, the gauge glass water is filthy, dark brown resembling chocolate milk. After a thorough clean and skimming, I get the water clear again and the surging subsides and no water hammer. However there are some installs I have to make multiple return visits just to find the new boiler is filthy again and again. Looking for any insight as to why this is happening. 

The way I was taught to skim was to let the boiler come to a hard boil, and to let the boiler surge and “puke” out all the foam and oil. I do this several times and then I will run a slow stream of water keeping the boiler hot until I have consistently clear water for about a minute. I’ll cap the skim port. Let the boiler run for about 10 minutes and repeat this process. After skimming twice, I then fully drain the boiler and do a final refill.

Any tips or info on what you guys do for skimming or if anyone has been having this problem if you have some insight I would greatly appreciate it.

ethicalpaul

That is not the skimming procedure that I think most people and manufacturers would expect (the puking part).

I like the Peerless instructions, here they are:






I did find my Utica was very prone to surging with dirty water. Are you piping both of the side-supply ports to the header?

KC_Jones

Boiling the water then trying to skim sounds like an exercise in futility.

The goal of heat is to allow the oils to flow better, but you are also trying to keep the surface as calm as possible the whole time. Boiling aggressively will tend to mix things up and possibly prevent the oils from coming out in a timely fashion.

Are you installing the versions that have 2 1/2" side outlets, or 2" side outlets?

If it's the larger size, then you need to reduce the skim tapping as the internal passages are on the small side and you end up only skimming the end section.

EBEBRATT-Ed

The skimming instructions @ethicalpaul are about the same as what I use and it always works,

clammy

I ve worked w guys who did the steam and puke method and then a slow skim and in most cases surprisingly it worked well . This being said this was usually w smaller 3 to 5 section boilers and back then nodody was wanding boilers most did nothing just installed and left. It does cut down on time and does work even though no one writes about . Too each his own . Personally I steam ,flush,wand ,fill steam and skim . Usually a good wanding from the bottom or on a peerless and also wand from the safety tapping which brings you through the supply tapping . With the way things are I completely understand why guys don’t wand and skim it’s mainly because everyone wants the cheapest price but want the highest quality work done by some one w a brain and experience but for a journey mens pay rate and of course everything that should be done by the book and who cares if your outta bussiness next week cause you can’t pay your bills . Cheap price hunting never pays the home owner still ends up w the same turd and will pay even more to correct that’s if there any takes .
I ve found that when replacing a boiler w wet returns that if they are not flushed of debrie or replaced that all debrie shall either make it way back to the boiler or you will end up w a clogged return . When looking at a boiler replacement job I always take a good look at the return if the system is close to 100 years old I advise that isolation valves and drains be installed to flush the returns if they opt not to I am up front w the fact that when I leave the boiler shall be clean but they will be charged for return visits to clean when the return debrie returns to roost due to not spending the money to have it done correctly from the start . Everyone would like to live forever and so would they like there wet return but truth be told after 50 to 100 years if you think there clean and clear I have a bridge to sell you . To really get a system clean after an install I would say generally it a few hours if your lucky and of course it ain’t happening for free,for that I’ll stay at home .
Peace and good luck clammy
The sweeten of a cheaper price is soon forgotten after the bitterness of poor quality

ChrisJ

@Crich199

Just to avoid any confusion and make sure we're all on the same page can you post some examples of how your boilers are being piped?

dko

Trivia: ECR is selling off the Utica manufacturing plant and combining Utica into Dunkirk's facility. Closed the Utica plant last month.

I would assume skimming should work the same whether for oils in a boiler or in cooking. You heat up and let it simmer. Then skim. Maybe the cooking partner in your home can teach you something about skimming!

Attached both Utica steam boiler manuals to save people few seconds looking them up