post install skim

mdmhh256 · October 31

Just had my 30+ year old utica gas boiler replaced by another utica. local firm that does a lot of boiler work and has a good rep. Install looks good, steel piping around the boiler that seems to line up with documentation on Utica website. As they wrapped up the job I asked about skimming and was told they did that. Several days later I see some black gunk at the top of the water line in the sight glass, and when boiler was running some water dripping/running into the glass from above. Called them back to ask about reskim and was told to let it run a couple of weeks (weather has been warm so far) and they would come back and drain and refill, no mention of skimming from what looks like a tapping port. Based on what I am reading I am not sure that is the right approach. Any advice ?

ethicalpaul · October 31

Skimming usually or often or always requires multiple "sessions" because it takes time for the oils to make their way into the boiler. Black gunk floating in the gauge glass is a clear sign that more skimming needs to be done.

Look in your boiler's manual which they should have left with you to see what Utica recommends.

mattmia2 · October 31

Is there currently some sort of nipple and cap or valve in the skim port? If it is just plugged they probably didn't skim it.

BobC · November 1

It's best to vot skim until the boiler has run a week ot two. This helps get any oild in new pipe down to the boiler where skimming can float it out of the boiler skim port.

As said abobe it can take a few skimming sessions to get all the oil up and this may noy ne imclufed in the install price.

Bob

Neild5 · November 2

Our boiler came with instructions written by the installer, in the first 6 weeks I had to skim it 4 times. He had valves clearly tagged and the skimmer line is long enough to safely drin to a floor drain.

mdmhh256 · November 5

There are two 2" pipes coming out of the boiler and running up to the header. One side has an "L", the other a "T" with a plug in it (see pic). Utica manual seems a bit much for me as it states "Fire burners to maintain water temperature of 180-200°F." Seems to be above my pay grade ? From other (non Utica specific) discussions on skimming I can just get boiler hot, wait for pressure to drop, then remove the plug and slowly feed water in and drain from the "T". Thoughts ? Also, how to tell when enough skimming has been done ?

Screen Shot 2024-11-05 at 11.29.12 AM.png

mattmia2 · November 5

Use the disconnect switch to turn it on and off. should not heat it to the point that it starts steaming so it won't build pressure. you can heat it with the cap off. Look carefully at the manual, some boilers require that you reduce the skim port with a fitting to raise the height of the water above where the sections join together.

mattmia2 · November 5

Also look at the pipe sizes in the manual for the header and risers, that reducer and smaller size riser may not be allowed.

mdmhh256 · November 10

skim in progress. Been going a couple hours and water is kinda the color of weak tea. Just wondering how clear it should be.

ethicalpaul · November 10

On a long enough time scale it will be completely clear, but it doesn't really matter very much. In skimming you are working to clear floating oily stuff. The color of the rest of the water is not critical.

mdmhh256 · November 10

ok. Thanks.

PC7060 · November 10

Can you provide a couple pics of the entire boiler and close piping?

mdmhh256 · November 11

pics attached

mdmhh256 · November 11

mdmhh256 · November 11

mdmhh256 · November 11

mdmhh256 · November 11

mdmhh256 · November 11

mdmhh256 · November 11

mdmhh256 · November 11

mdmhh256 · November 11

mdmhh256 · November 11

also - utica cleaning instructions. I skimmed for maybe 3 hours. As noted above water at end was brownish like weak tea. Then i blew down 4 times. Water still coming out dirty. Now time for bed. Won’t get back to this for a couple of days.

mdmhh256 · November 14

Back to checking out my boiler.

When I left off several days ago I had done several blow downs. Even from the last one the water appeared dirty, so I left 5 or 6 five gallon buckets filled with the what got drained off. Several day later all the sediment had settled to the bottom and the water looked pretty clean.

Still getting dirty water when I drain, but the sight glass looks pretty clean.

Now when I run the boiler the water in the sight glass seems to bounce around somewhat more than the inch indicated by the manual. Also, I can see some water running down into the sight glass from above. Normal ?? I don;'t remember seeing this on my old boiler.

ethicalpaul · November 14

that is an indication that you still have some surging and need more skimming.

It's not necessary to skim for hours and hours each time. It takes time for the oils to flow down to the boiler, so several skimming sessions are often required. I sound like a broken record.

I'm not sure what your skimming setup is, but you might consider a reducer to 1-1/4" on your side supply tee if that's what you're using to skim. This lets the water level rise in the boiler so the oils can travel between sections to escape.

Don't worry too much about brown water out of the drain, this is going to happen. After a skim you get to drain quite a bit anyway to return the water level to its operational level so don't sweat it.

delcrossv · November 14

https://forum.heatinghelp.com/discussion/comment/1820139#Comment_1820139

It's fine, take another look. 😉

ChrisJ · November 14

https://forum.heatinghelp.com/discussion/comment/1820134#Comment_1820134

You're skimming from that tee on the supply line, correct?

ethicalpaul · November 14

https://forum.heatinghelp.com/discussion/comment/1820140#Comment_1820140

I did, hence the deleted (then edited) post 😅

mdmhh256 · November 14

skimming from here….

Screen Shot 2024-11-14 at 12.53.07 PM.png

STEAM DOCTOR · November 14

Personal experience. Not sure why this works. Put some eight way (or scale flush) into the boiler. Fill till close to top of glass. Run the boiler for 30-60 minutes. Truthfully, boiler doesn't need to run the entire time. Just needs to be hot. Once water starts to bounce, shut boiler. Wait 10ish minutes and turn boiler back on. When water starts to bounce, shut, wait, repeat. After hour or so, drain the boiler to bottom of glass but not future, so incoming cold water doesn't shock the boiler. Fill to header and repeat until water comes out cold/cool warm. Fill to the header and drain all the way out. Repeat a few times. Not really sure why this works, but it does absolute wonders and cuts hours off of skimming time.

mdmhh256 · November 14

a couple posts asked if I was skimming from the supply T. By that I presume you mean the one in this pic ?? if so I am a bit confused. utica instructions say to skim from the upper T (in my previous picture). I posted there cleaning instructions above as well. how does process work if I am skimming from that lower T?

Screen Shot 2024-11-14 at 2.15.52 PM.png

delcrossv · November 14

No, it's the steam supply Tee (the upper one you're presently skimming from)

mdmhh256 · November 14

got it…. i was confusing water supply to to boiler with steam supply to the header

ChrisJ · November 14

https://forum.heatinghelp.com/discussion/comment/1820171#Comment_1820171

https://forum.heatinghelp.com/discussion/comment/1820195#Comment_1820195

No, you're good.

The upper tee that your showed originally. You're doing it correctly.

The lower one would be the return.

mdmhh256 · November 22

making progress… thanks for the advice….

I was not clear on the part about 1 1/4" reducer until I removed the 2" plug on the skim T and peered in with a flashlight. Now I can see the water rising above all of the sections and flowing out. I think I also saw some sheen on the water surface, I presume an indication of oil. (The shop did not have a 2 to 1 1/4 reducer, so I put in a 2 to 1 reducer. Seems to do the job.)

At this point the water running down from the top of the sightglass looks to have been resolved. Water level still bouncing but maybe within tolerance.

I may do another 1 or 2 short skims.

mdmhh256 · November 25

still skimming. I have been capturing the first few ounces in a small container to see how it looks. This from just now.

AdmiralYoda · November 25

That's the stuff! Keep doing short, quick skims to get rid of that.

BobC · November 26

Wheb you skin the output stream should be the size of a pencil, any fatter and you will roil the water - you want the water in the boiler nice and quiet so you can float ant oils out that skim port.

Bob

EBEBRATT-Ed · November 26

If it was me I would add TSP or washing soda. 1 LB of it does 50 gallons of boiler water so you have to adjust for how much water your boiler holds so you may need only a 1/4 lb or less. Run the boiler until it starts to steam with the water level at 3/4 of a glass full with the tsp in it and shut it down. Drain boiler to height of skim tapping and when pressure is gone remove plug from skim tapping feed water in slowly and skim. Water out the skim port should be the size of a pencil. Skim until oil is removed. Drain boiler replace skim cap.

Let the boiler cool. Then fill and drain the boiler twice then refill and put boiler in operation

Works every time. I usually wait a week after install to give the boiler some run time.

I have never had to skim more than once and a hour or so of skimming does the job

JMHO

You need something to break the oil loose not just steam and water.

post install skim

Comments

Categories