Water line over 2” drop

trivetman

Heres my water line on a cold start. 

 

After 10 minutes of steaming,  its over 2”, maybe 2.5” inches lower.

It’ll stay that low through the duration of the cycle.  The LWCO  is a cycleguard with intermittant cutout.  During the cutout the level in the sight glass does not change.  The low water light occasionally lights up for a second or so but not long enough to trigger a fill.  Autofill is at one gallon for the season so far.

Any reason to raise an alarm, or leave good enough alone?  Boiler was installed last spring and is getting all the rads hot and the old drafty house is as evenly heated as I could hope for.  Piping seems to be done correctly.  I had some pressure surging earlier in the year but now seem to have skimmed and cleaned enough thats not an issue anymore.  There is some gurgling noise to the system on a cold start (though its much quieter than the old steamer) My best guess is my mains (the entire perimeter of 1000+ sq ft basement is hung close to the rafters) have no slope and condensate is collecting in the mains and not fully draining.

a few more pics to give the full picture…

EBEBRATT-Ed

If the mains were not pitched right you would most likely get water hammer but I would check the mains with a level. I would be inclined to think it may be a return issue. Shut the boiler down when the water is at it's lowest level and see how long for the water to come back up.

As long as your are not constantly tripping the LWCO you should be fine. The newer boilers hold less water than the older boilers. How are your main vents?

mattmia2

How long does it fall after it starts? Are the risers out of the boiler the size of the tappings? they look like they've been reduced.

trivetman

@EBEBRATT-Ed

mains are level in every spot i can measure.  They seem perfectly level until the very end of the run when they pitch down. The dry returns seem to have a proper pitch to them.  Pretty sure the venting is in good shape.  When i first bought this place (7 yrs ago?) nothing heated evenly and someone (steamhead?) had me measure the piping and told me what vents to put in.  In any case, the ends of the mains both get hot around the same time (~7 min from a cold start) and all the rads start heating probably within a minute or so of one another.

I don’t know exactly how long it takes for water to rise back up to the start position.  I know its less than 15 minutes or so but it might be as quick as 5 minutes.  Ill try to time it tomorrow.

Main vent #1


Main vent #2

Dry return vent

trivetman

mattmia2 said:

How long does it fall after it starts? Are the risers out of the boiler the size of the tappings? they look like they've been reduced.

its a 2” pipe expanded to 3” riser and header.  Pretty sure the tapping is 2” and I don’t think anything is reduced where it shouldn’t be.

ill try to watch a cycle tomorrow and time how long it takes for the level to drop

109A_5

Hello @trivetman,
I kind of wonder if you are trapping water in the main, probably should be an eccentric coupling or changed so it drains properly.

trivetman

@109A_5

that makes a lot of sense.  The rads which branch off right before that reduction are the most gurgly sounding.  

I'll have to check the reduction at main vent #1 tomorrow to see if its got a similar blockage point. I cant see it clearly in the picture.

fixing that’s probably beyond my skill. Even if the threaded joints come apart easy, I can sweat 3/4 copper without too much trouble but think that 1” might be pushing my luck.

trivetman

So i think theres a reduction problem on both mains.  The reduction to the copper on vent #2 isn’t as bad as on #1

But 8 feet prior to vent #2 is this reduction 

These bottlenecks can possibly be fixed with some expense that doesn’t break me.  What I can’t fix without major surgery is the 150 feet of steam mains hanging without any pitch at all.  So if I fix the reducing couplings, does it solve the problem?

as far as timing,  I took a closer look at the cycle this morning 

the water line gets to that low point after about 11 minutes of steaming (17 minutes from cold start).  I MUST still be having some foaming for the lwco to not be triggered when its this low.


1 minute after shutoff (I don’t understand why the lwco isn’t triggered here but its not)


2 minutes 

5 min

10 min

30 min all the water is back (had to leave for a bit!)

Jamie Hall

And it takes a while to come back up after the boiler shuts off? Slow returns. sometime when it warms up again, see if you have any way to flush them out.

ethicalpaul

Yeah, @trivetman initially I liked your diagnosis of your "flat" mains resulting in slow return but I wouldn't expect those to make your water level continue to drop even more during a long call for heat.

So right now I'm with @Jamie Hall that your wet returns are suspect. Are they old? Partially clogged?

I don't suspect surging too much because of the timing and behavior you describe, but that is still possible too. It's just too difficult to say from here with certainly unless you have sight glasses on your near boiler piping.

Regarding your water getting low without triggering your LWCO, I wouldn't say you "must" have some foaming...boiling water is violent and can fool a probe LWCO--that is why the CycleGard exists (I still don't know why everyone hates on it so much.

trivetman

Its not the wet returns being clogged.  Just a few weeks ago I flushed them out following an extended skim as I was having pressure surging to the point it was cutting out on pressure.  Plenty of filthy water came out but nothing thick and the water was flowing unrestricted.

The only possibility of a clogged return would be in the vertical drop as that was outside of the path being flushed.  Seems unlikely.

This is a problem I can live with as long as it doesn't get worse and start triggering the lwco and flooding the boiler.  Just trying to figure out if I should try to do something at this point.  I think its a combination of flat mains (not changing those) along with flow restricting reducing couplings (can probably change those)

I also like the cycleguard.  Its a good preventative idea, especially as most people don’t ocd monitor their boiler like some of us do.  I am just surprised its not coming on with how low my water level is getting.  See that pic 1minute after shutoff.  The level in the sight glass is at least half an inch under the bottom of the fitting connecting the lwco into the boiler

ethicalpaul

OK if you are sure that your returns are OK then it must be the mains not having enough pitch and/or surging. There's literally no other place the water could go.

What do you mean by this term "pressure surging" that you keep using?

trivetman

ethicalpaul said:

. What do you mean by this term "pressure surging" that you keep using?

I should probably be saying ‘pressure from surging’

When my water has been very clean (right after a skim) the boiler will run for at least 45 minutes without building more than 2 oz of pressure at the gauge.  After the oils have had a chance to accumulate,  the pressure at the gauge and vaporstat has gotten very high right after steaming has started, to the point where the vaporstat cuts out at 12 ounces and it starts to short cycle.  Ive seem this happen 3 or 4 times now and its always been fixed with skimming.  Until this past time,  the short cycling is back within a week or two of skimming.

The boiler was just installed last spring.  Its been a month since I last skimmed it so I hope I am past the point where its a short cycling problem.  The pressure is running around 8 oz now once it gets steaming, so there probably is still some foaming causing localized pressure but its not so bad it’s triggering a pressure cutout.  This might be throwing some water into the mains as well?

mattmia2

Too much of that purple stuff will cause the water to foam (surge). Combined with that maybe a little iffy sizing and height with the risers that could cause some carryover.

It would be worth pulling the lwco probe and making sure it is clear in to the boiler.

If it is having trouble steaming because there is oil on the surface of the water that can't build pressure, the vents won't be closed until the boiler makes steam and the heat from the steam reaches the vents. Something else is happening there but I'm not sure what from your description. I suspect it is not oil and surging.

109A_5

The CycleGard may have delays too.



Personally the whole stopping the fire to test, the "CycleGard Intermittent Level Test Feature" is just a gimmick. Should the water level get low enough during a burner event the LWCO should shut down the burner without the need for interruption for testing. And it should be monitoring the water level in-between burn events anyway. Some folks seem to like the burner interruption to help mitigate their pressure issues.

If your boiler runs 24/7 then I can see the feature as a value but I think most residential boilers don't run 24/7.

109A_5

Hello @trivetman,
Just the size of your system and (newer boilers hold less water) may be part of the reason the water level drops. Your water getting contaminated so quickly bothers me. Maybe if there is puddling in the mains there is also more mud generated there to.

trivetman

Thanks all for the ideas.  I am in no rush to do any work on the system now as it is heating the house just fine and the loss of water isn’t so much that its triggering auto-refill.  I might talk to the installer about changing out those couplings next time he’s here for maintenance.

109A_5

Hello @trivetman,
Yes, repairing those areas where the condensate may be puddling may seem relatively easy, but if it has been that way for many years the pipes may be dilapidated and it may turn into a bigger project.

trivetman

Understood