Missing Skim Tapping? How to skim then?

GBC_illinois

Thanks in advance for all the help you pros provide. I'm a semi-noob learning to manage the steam boiler in my building. The sight glass is bobbing up and down, and I've recently learned that a common solution to this is "skimming" the boiler. I do not think this has ever been done on my system.

Also, I don't think the sight glass bobbed up and down until last year, when we had two cracked cells replaced (long story there!). It is my suspicion that when they replaced these cracked cells, they did not skim the boiler afterward. Anyway, from my research it seems like skimming is at least something I should be able to do from time to time, and I don't know how, because the skim tapping does not seem to have been "tapped" if you will. Photos are below, but here are the boiler specs:

Weil-McLain LGB-9 Series 2 boiler
2-pipe steam
Runs very well at about 0.78 psi max (I said 0.6psi earlier, but the installation of a new pressure gauge has corrected me)
15-unit shared building

My questions are:
1) Since the normal skim tapping port was never opened, is there a different port I should use (there are a bunch of capped but accessible smaller ports on the back)? Or should I make an effort to access that port? If I took the jacket off would I see a plug there that I can remove and install a 2" pipe onto?

2) All the instructions I've read say to "add water slowly" while skimming. How is that accomplished when we have a pumped return activated by the boiler's water level? I'm not aware of any other way to add water than the pump, and the pump is very fast.

ethicalpaul

J1 is your pal but M1 or E1 could be used. If they are under the jacket or not accessible for some reason you could use your pressure relief valve tapping shown in your photo of your boiler.

You add water slowly by cracking open the manual valve that should be on your water feed line. It should be near your autofeed, like piped to go around it.

by the way, I agree completely with your thought that your boiler needs to be skimmed. If they replaced sections and didn't skim it, that's not good

GBC_illinois

ethicalpaul said:

You add water slowly by cracking open the manual valve that should be on your water feed line. It should be near your autofeed, like piped to go around it.

Thanks @ethicalpaul . I think the only valve on the water feeding into the boiler is on the outlet from the boiler feed pump, which is always kept full-on. (I'm not even sure why it's there? Wouldn't cutting off the flow from a pump outlet quickly burn it out?) . Do you suggest that I throttle this valve from the pump, keeping it on just a trickle, while I force the pump to run continuously?

We do have a water feed line, but it goes into the feed tank, and not directly into the boiler itself anywhere that I can see. I've attached photos.

GBC_illinois

@ethicalpaul I think I've figured out a solution to add water. If I open the cap on the top of my control tree, I can feed water in that way from a water bucket on top of the boiler jacket. An extra benefit of this method is I can use hot water to feed into the boiler (I'm nervous about adding cold, after we had two cells crack a couple years back).

Then, I can open the E1 or M1 on the back side (you can see they are sticking out and just capped) and drain into a bucket there.

Does that sound reasonable?

EBEBRATT-Ed

@Fdarby82

The bucket method for filling isn't very good. The picture of the front of the boiler has a garden hose attached to a drain valve. You can take that short hose off and feed water in their.

Use a regular garden hose and a female x female hose adapter (or an old washing machine hose) hooked to the garden hose to attach to the boiler.

Then you have to find a source of water for the other end of the garden hose like from a hot water heater, or a slop sink or a washing machine valve etc.

You want to skim slowly the water coming out should be the diameter of a pencil

ethicalpaul

Thanks for coming in at the perfect time @EBEBRATT-Ed ! I didn't know he had a condensate tank setup so it got over my head fast.

While we're talking about this condensate tank. Why is there a condensate tank only 4 feet away from the boiler? Couldn't the return go right to the boiler so much simpler?

EBEBRATT-Ed

@ethicalpaul

Lots of steam traps in the pictures. Guess that's why they needed the boiler feed tank. Not enough height for gravity return

GBC_illinois

@ethicalpaul @EBEBRATT-Ed I'm hoping to eventually return this system to gravity return, but I've not done the necessary measurements to verify it can run that way. I suspect it did, years ago.

Thanks for the advice on the hose method, EBEBRATT. That sounds much better than the bucket!

EBEBRATT-Ed

@Fdarby82

based on the height of some of your steam traps in the pictures I don't think you could run gravity. You need some height to overcome the boilers steam pressure to put condensate back in the boiler

Hap_Hazzard

Fdarby82 said:

I'm nervous about adding cold, after we had two cells crack a couple years back.

"Thermal shock" is rarely the reason boiler sections crack. In the case of this boiler, it probably had more to do with the number of risers. Unless I'm mistaken there's only one, am I right? Which sections failed?

GBC_illinois

Hap_Hazzard said:

Fdarby82 said:

I'm nervous about adding cold, after we had two cells crack a couple years back.

"Thermal shock" is rarely the reason boiler sections crack. In the case of this boiler, it probably had more to do with the number of risers. Unless I'm mistaken there's only one, am I right? Which sections failed?

@Hap_Hazzard since it sounds like you want the story, we had a problem with the boiler that we didn't realize was happening: The electrical relay which controlled the pump on the boiler water level was bad, so 99% of the time, it would correctly respond to the float activating the pump, and 1% of the time it would not. So we had a mysterious issue where the pump would just run continuously, flooding the boiler, because the relay didn't switch back to "off" after the water level was satisfied.

In December 2020 -- before anyone even knew the boiler periodically flooded (I had only purchased my condo a few months prior, and no one else in the association was active in monitoring the boiler) we had two boiler cells crack. These were the two cells closest to the water inlet from the feed pump. At the time it was a mystery. But after replacing them, 2 weeks later, the boiler pump failed -- another mystery. All in, replacing these two things cost us $11,900.

January 2021 -- I'm now learning about and monitoring the boiler, after realizing how much money we sink into it in repairs. One late January morning, we discover water is pouring into the basement from the 1st floor. I thought a bathtub faucet was left on, but it turns out that one of the radiators on the first floor had a big leak, and combined with this being one of the rare times that the relay didn't respond, the boiler had flooded, the water level inside the steam pipes was 10 feet higher than the normal boiler water line, halfway up the first floor. The pressure gauge was reading 15psi or so on a boiler that, at the time, ran at about 7psi, the excess I later learned from actual inches of water column. This was the first time I learned that the flooding was even occurring, and it would be a long time before I figured out why.

Even though I didn't know why the flooding had occurred at that time, the evidence now seemed clear that this flooding was the root cause of both the pump failing in December (now that we knew it can run for hours on end when the issue occurs, instead of about 5 seconds at a time like normal), as well as the boiler cells cracking. The fresh water feed line is always open into the boiler feed tank, and tops it off with water as necessary. With the pump running continuously, it quickly exhausts the tank, then pulling fresh, cold water from the tap to directly pump into the boiler, and we have a big, quick pump.

As I was still a true boiler noob at the time, I called contractors to figure out the flooding issue. It was impossible to re-create it; I had to just wait until the issue occurred to have a chance to diagnose it. In the meantime, I turned off the fresh water feed to the tank and only added fresh water manually every week or so, to avoid the cold-water-rushing-directly-into-boiler scenario, if I wasn't there to catch it. At least then, it would just pump nothing into the boiler. I called contractors to help me diagnose the problem: two different companies recommended we replace the entire float assembly for $2000-3000, but I could tell by my own novice analysis that the float was operating correctly -- I can maneuver the end of it with my finger and see that it goes up and down with the water level. So I assumed it must be the "snap switch" which the float presses against. I replaced that for about $500, but it did not fix the issue. I was baffled. Only much later did I realize that the snap switch then goes into this separate electrical relay (I would hear it snap loudly whenever the pump activated). Replacing that part -- for $9 -- fixed the issue. And, I think it is 99% likely it would have prevented the $11,900 in repairs from December. Mind you, none of the contractors mentioned this part. So, you can understand why I've taken on all responsibility for managing this machine myself.

But the short answer to your question is that I would bet a lot of money that in my case, it was cold water which caused the cells to crack.

GBC_illinois

EBEBRATT-Ed said:

@Fdarby82

based on the height of some of your steam traps in the pictures I don't think you could run gravity. You need some height to overcome the boilers steam pressure to put condensate back in the boiler

@EBEBRATT- There are some things that are not visible in the photo which might change your mind. You can see the two upper steam traps, over head height, and two lower traps, around thigh height. Those lower traps are from lines that, immediately before what you see here, go under a staircase. The last risers to radiators are before the staircase. Before the staircase, the steam and condensate line are about 75" off the ground, only slightly lower than the two higher steam traps you see in the photo.

Does that change your mind about whether I could run on gravity if I wanted to put in the effort? I would love to make this change someday if the pros think I can.

GBC_illinois

@EBEBRATT-Ed here are some photos of the area before the staircase.

EBEBRATT-Ed

@Fdarby82

No the lowest trap rules.

But on to the other problem. I just skimmed through your flooding issue. What you should do that I highly recommend is install a "spill" Or "dump" trap. This is a steam trap mounted on the boiler equalizer line at a height level with the top gauge glass nipple. This traps outlet goes back to the boiler feed pump. So if the water in the boiler gets too high (like the pump sticking on) this trap will dump the water back to the feed tank.

I don't know if this is in the LAOSH, I think it is, I will have to look tomorrow

GBC_illinois

EBEBRATT-Ed said:

@Fdarby82

The bucket method for filling isn't very good. The picture of the front of the boiler has a garden hose attached to a drain valve. You can take that short hose off and feed water in their.

Use a regular garden hose and a female x female hose adapter (or an old washing machine hose) hooked to the garden hose to attach to the boiler.

Then you have to find a source of water for the other end of the garden hose like from a hot water heater, or a slop sink or a washing machine valve etc.

You want to skim slowly the water coming out should be the diameter of a pencil

@EBEBRATT-Ed Just wanted to let you know this worked great, using the garden hose method. Thanks for the advice!

I skimmed it for a couple hours, but I was surprised at how crystal clear the water was. I could barely detect any oil sheen at all in the bucket I was skimming into. If I dipped my finger into it I could feel a bit of slippery-ness. Overall, I'm beginning to think oil on the surface probably isn't the root of my sightglass bounce issue, although the problem might be slightly improved now.

ethicalpaul

IMO if you saw a sheen and could feel the oil, then skimming was productive. You don't want that in there. It's not going to be like that Dawn ad where the ducks have oil on them