Skimming a new boiler - Frequency?

cluelessandlost

Hi all, just got a nice new steam boiler installed today and I am reading conflicting information about how often to skim. My installer said I could skim every day (fill up 3/4 of a bucket) for the next 2 weeks. The boiler manual says to do a marathon session without closing the valves until the water temperature is no longer hot to the touch (without a thermometer, I'm not too keen on testing this approach to be honest). But I'm also reading posts on this forum that suggest waiting a week between skimming to let the system run for longer.

Which approach here would be best?

109A_5

Hello cluelessandlost,

If you are going to do it yourself, IMO I would start to do it ASAP. The more oil you get out sooner the less chance it has to migrate to other parts of the system if surging starts. Once the oil is spread throughout the system the longer it takes to return to the boiler to eventually get purged out with skimming.

How much oil is in your system ? Who knows, you may have to skim a lot or it may go fairly quickly. I don't know if there is a perfect method, I do know it needs to be done.

cluelessandlost

I've spent about 3-4 hours skimming a bucket before calling it a day today (it's pretty cold here so I didn't want to be without heat for too long). I just didn't know if I should wait a longer period of time before skimming again or do it daily. It sounds like for a new boiler it might be better to do it more often, or at least sooner rather than later?

109A_5

Its one of those things that you need to do as much as needed, When you stop seeing oil in the bucket and the waterline in the sight glass is clean and the the boiler boils calmly you may be done, or near done. It can be a process, every system is a bit different.

EBEBRATT-Ed

The determining factor of weather to skim or not is to watch the gauge glass while it is steaming.

If the gauge glass keeps getting dirty and when steaming the water level is bouncing or violent movement up and down more than 1" or water coming into the top valve on the gauge glass and running down, then you need to skim.

When it is skimmed enough the water level should be steady or gentle movement up and down of not more than 1" is ok.

I prefer to skim using washing soda but that is another story.

I prefer skimming after the boiler has been running for 5 days or a week or so then you usually can get it done with 1 long skim. Usually, an hour or so will do it.

If you want to do smaller skims more often that is fine too. Makes no difference in the end.

The reason for waiting is to move any crud from the piping back to the boiler after the piping has been disturbed by the install. Then you only have to do it 1 time.

cluelessandlost

I've been skimming about 2 buckets a day for the past 2-3 days, and I noticed something that I'm not sure is odd or normal. The water that drips into my bucket from the skim port is slightly dark/translucent with an oily film on top, so I am hoping that's a good sign I'm getting the oil out. But in the final step when I open the drain valve to let the water fall back to the proper level before turning the boiler on, the water that comes out of the drain valve is always really dark/dirty.

Should I let the drain valve run longer until the water is clean and then refill the boiler until it reaches the right level in the sight gauge? Right now I'm just stopping the drain valve once the water level drops from the skimming level to the correct level in the sight gauge and then turn the boiler back on.

EBEBRATT-Ed

Just keep skimming at the skim point. Any oil will be on top of the water and removed by the skim. Drain the boiler after you have completed skimming. When cool or luke warm refill Drain and refill again then put into operation to drive the oxygen out.

Are you skimming with TSP or washing soda?

cluelessandlost

No, I'm just skimming it without anything added at all.

EBEBRATT-Ed

@cluelessandlost

This is JMHO but skimming without washing soda to me is like putting clothes in a washing machine without any soap and expecting things to come out clean.