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water level in boiler, what is normal?

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When my boiler runs the water level seen in the sight glass moves down until it's below the bottom of the glass, but then it rises back up again, and this cycle repeats a few times over the course of a few minutes. I imagine that the water level would maybe be expected to go down as water converts to steam and goes up into the pipes?

However, I believe that this sometimes triggers the low water cutoff. It doesn't happen all the time, but I have seen it happen.

Here's a video of the water in the sight glass as this happens:
https://photos.app.goo.gl/s2nUmEtoifei384KA

Oh, and this is single-pipe steam, Weil Mclein boiler, my first winter in the house, but the boiler is just a few years old.

Thanks for any suggestions!

Comments

  • Dave_61
    Dave_61 Member Posts: 309
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    I'm just a homeowner, but I've hung around the site alot, and it sounds like your relatively new boiler was never skimmed for oils etc that are from the manufacturing/installation process. This causes water level fluctuations. If you have the manual, you can find your skim port and slowly skim the impurities out.
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
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    Guaranteed your boiler is "carrying over" gallons of water into your mains. You don't want this condition. As @Dave_61 said, you need to skim your boiler. The water color and suds are a tipoff too.

    (that amount of water loss is far far too great to be accounted for by steam production)
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    JUGHNE
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
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    Also post photos of your near boiler piping, if poorly laid-out, that can exacerbate the issue.
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
    CLamb
  • roberts
    roberts Member Posts: 32
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    Thanks for the feedback! Is skimming the boiler something I can do myself? Any good resources with instructions on how to do this? I'll do some searching but would appreciate if anyone has some tips...
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,530
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    normal water lever is 1/2 a gague glass full......unless the boiler mfg has a slightly different level. The rule of thumb is if you can see water in the gauge glass the boiler is safe to run if you cant seee water its not safe to run, When the boiler is steaming it is normal for the boiler water level to drop somewhat but mot out of the glass. The water level shouldn't bounce more than an inch or so while steaming.

    In general violent water movement mean something is wrong with the piping or the boiler water is dirty and needs skimming. If the water bounces slowlry it is usually fine. your boiler may need skimming
  • mattmia2
    mattmia2 Member Posts: 9,660
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    Also possible it isn't equalized properly and the pressure is pushing the water in to the returns.
    CLamb
  • JUGHNE
    JUGHNE Member Posts: 11,062
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    Surprisingly, there appears to be a skim port set up on the boiler.

    Just what you need.

    But more pictures floor to ceiling all sides will get you more answers.
  • mattmia2
    mattmia2 Member Posts: 9,660
    edited December 2022
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    That water looks foamy. It may be too much additive causing priming rather than oil causing surging.

    Show us the near boiler piping, it looks a whole lot like some pressure builds in the boiler, pushes the water out in to the return, the level goes below the hartford loop, steam/air burps over in to the return and equalizes the pressure, the water returns because the return pressure is near the supply pressure, then the cycle repeats as more pressure builds in the boiler.
  • roberts
    roberts Member Posts: 32
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    Thanks everyone! Here is a video attempting to show the near-boiler piping:
    https://photos.app.goo.gl/M2JnGEHe9zJ7u5fv6
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,530
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    What model is that boiler?

    The piping looks ok but the riser header and equalizer may be undersized
  • roberts
    roberts Member Posts: 32
    edited December 2022
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    Thanks, it's a weil mclain. I'll look up more specifics in a bit.
  • roberts
    roberts Member Posts: 32
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    Okay, here's the details on the boiler:

  • neilc
    neilc Member Posts: 2,703
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    wondering if the pigtail is clogged
    known to beat dead horses
  • mattmia2
    mattmia2 Member Posts: 9,660
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    Could the priming be throwing enough water in the equalizer that it can't equalize?
  • neilc
    neilc Member Posts: 2,703
    edited December 2022
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    hummm,
    there is violence in the boil as evidenced by the carry over in the sightglass ,
    needs skimming,
    known to beat dead horses
  • ethicalpaul
    ethicalpaul Member Posts: 5,702
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    mattmia2 said:
    Could the priming be throwing enough water in the equalizer that it can't equalize?
    Or it’s going right up the main, or what you said, pushing out the back due to pressure
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • roberts
    roberts Member Posts: 32
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    @neilc
    neilc said:

    wondering if the pigtail is clogged

    Do you mean the pigtail that connects the pressure gauge and pressurtrol? Now that you mention it, I've never seen the needle move. I thought it was because it was less than 1 on a scale of 30 but maybe I should still see some movement on that needle.

    If that pigtail was blocked what issues would that cause?
  • roberts
    roberts Member Posts: 32
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    Regarding skimming, I have some questions. Looks like the skim port is above the usual water level, and then there is a lower drain presumably at the bottom of the tank. I suppose I just need to open the skim port valve, with a bucket below it, and open the feeder valve a little until water starts to drain?

    I did that a bit this morning. Water coming out was brown but not terribly thick or anything. Should I be doing this while the water is hot? How much water should I skim off of it? I probably took about two gallons this morning.

    Oh, and don't do what I did this morning which is to dump that water into a basement slop sink connected to an ejector pump. The pump immediately shut down due to the high temperature of the water. I didn't realize it right away so I had a bit of a mess as it overflowed the pump basin. Thankfully the pump cooled down and started working again but not without causing me to panic for a couple hours!

  • ethicalpaul
    ethicalpaul Member Posts: 5,702
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    Your skim description sounds OK. You aren't looking for "thick" water, you are looking for a sheen of oil floating on the water that is exiting the skim tap.

    You should heat the water to near boiling, but not yet boiling, then shut it down and start the slow water feed.

    What kind of ejector pump do you have that is sensitive to water temperature?
    NJ Steam Homeowner. See my sight glass boiler videos: https://bit.ly/3sZW1el
  • roberts
    roberts Member Posts: 32
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    What kind of ejector pump do you have that is sensitive to water temperature?

    I have something like this:
    https://www.zoellerpumps.com/product/drain-pump-series/

    The specs on that pump say maximum operating temperature of 130 degrees F. That makes sense if draining residential hot water, but I guess the water from the boiler was well above that.
  • JUGHNE
    JUGHNE Member Posts: 11,062
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    What has worked for me skimming:

    Bring water up to near boiling.
    Shut power off.
    Let steam pressure, if any, dissipate.
    You can carefully check for pressure by cracking the skim port open.
    Start adding water slowly....assuming your water fill is well below the water line.
    Let the water slowly rise up to the fully open skim port.

    You want the skim port fully open to pass a very small steady stream of water into the bucket.
    You control the flow by cold water fill valve....not the skim port.

    I let it flow until water is cool coming out of skim port.

    You can use several buckets allowing the water to cool off before dumping into pit.

    This process may take several hours.

    You are slowly floating the oils and scum off the top of the boiler water.
    Draining the bottom of the boiler will not remove the oils, they will adhere to the sides of the sections inside of the boiler.

    After you are done, drain the boiler down to the normal level and you must fire the boiler to boil off any O2 from the fresh water.....this helps preserve the cast iron from rusting.

    I would suggest a cap screwed snugly onto your skim port nipple, it is easy to knock that ball valve open and get a steam bath.
    roberts
  • roberts
    roberts Member Posts: 32
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    Your skim description sounds OK. You aren't looking for "thick" water, you are looking for a sheen of oil floating on the water that is exiting the skim tap.

    You should heat the water to near boiling, but not yet boiling, then shut it down and start the slow water feed.

    Thanks for that.

    I just found this nice description of skimming. I'll have to give it a shot this way:
    https://mechanical-hub.com/steam-boiler-skimming/

  • roberts
    roberts Member Posts: 32
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    Okay, I think I gave it a pretty decent skimming, thanks to all the above comments, especially @JUGHNE for the detailed explanation.
    Firing up the boiler after the skimming was complete, the water level in the sight glass seemed quite a bit better. But, after watching it a while, it did take some substantial deviations. Maybe a second skimming is worth a shot?

    But now I've become more aware that the pressure gauge has never moved a millimeter. I think soon I'll take a stab at removing the pigtail to see if I can clean that out. I figure the pressuretrol is likely not doing its job at the moment...
  • JUGHNE
    JUGHNE Member Posts: 11,062
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    You might wait a few days before skimming again.

    If you have an iron pigtail and it hasn't been cleaned for a while, you might consider getting a copper replacement, they stay clean longer.
  • Don_175
    Don_175 Member Posts: 126
    edited December 2022
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    roberts said:

    Okay, I think I gave it a pretty decent skimming, thanks to all the above comments, especially @JUGHNE for the detailed explanation.
    Firing up the boiler after the skimming was complete, the water level in the sight glass seemed quite a bit better. But, after watching it a while, it did take some substantial deviations. Maybe a second skimming is worth a shot?

    But now I've become more aware that the pressure gauge has never moved a millimeter. I think soon I'll take a stab at removing the pigtail to see if I can clean that out. I figure the pressuretrol is likely not doing its job at the moment...

    I skimmed my boiler once a week for a total of 3 times. each time I noticed a little improvement over the previous time. My sightglass used to go almost completely empty with the boiler running. Now, it stays within an inch or so of the normal level when steaming. It still bounces an inch or so from time to time but nowhere near as much as it used to. As far as the pigtail, mine is brass. Supposely doesn't clog as much as iron. I have never seen my 0-30 gauge move. It's really just a safety device. I added a 0-3 psi gauge onto the pigtail and my boiler typically runs around 0.6-1 psi.
  • Don_175
    Don_175 Member Posts: 126
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    roberts said:

    Okay, I think I gave it a pretty decent skimming, thanks to all the above comments, especially @JUGHNE for the detailed explanation.
    Firing up the boiler after the skimming was complete, the water level in the sight glass seemed quite a bit better. But, after watching it a while, it did take some substantial deviations. Maybe a second skimming is worth a shot?

    But now I've become more aware that the pressure gauge has never moved a millimeter. I think soon I'll take a stab at removing the pigtail to see if I can clean that out. I figure the pressuretrol is likely not doing its job at the moment...

    I skimmed my boiler a total of 3 times over several weeks. It now doesn't fluctuate nearly as much. My sight glass used to empty out almost completely. Now it stays within an inch or so of the normal level when steaming. It still bounces a little but not like it used to. I added a 0-3 psi gauge onto the pigtail as you will not see the 0-30 gauge move unless there is a problem with the boiler. Mine runs at about 0.6-1.2 psi.
    roberts
  • KC_Jones
    KC_Jones Member Posts: 5,739
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    roberts said:

    Okay, I think I gave it a pretty decent skimming, thanks to all the above comments, especially @JUGHNE for the detailed explanation.
    Firing up the boiler after the skimming was complete, the water level in the sight glass seemed quite a bit better. But, after watching it a while, it did take some substantial deviations. Maybe a second skimming is worth a shot?

    But now I've become more aware that the pressure gauge has never moved a millimeter. I think soon I'll take a stab at removing the pigtail to see if I can clean that out. I figure the pressuretrol is likely not doing its job at the moment...

    Do not obsess over the pressure. The 0-30 psi gauge on the boiler will most likely never move. Steam heating wants as close to zero pressure as possible. Pressure, honestly, means problems. Could be the common oversized boiler, to bad piping, lack of venting. Pressure is bad and you don't want it.

    If you have a good system and want to know pressure, add a low pressure gauge and you can see what you are getting. I have a 0-15 ounce gauge and it barely moves, I think I've seen it hit 4 ounces before, but that was when I was surging after install. If you think you are getting up to the pressutrol cut out in the 1.5-2 psi range, then do a 0-3 psi gauge, and plan on downsizing the boiler if you ever replace it as it's most likely over sized (maybe just slightly) to be able to hit those pressures.

    Some will argue that point with me and that's fine.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • roberts
    roberts Member Posts: 32
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    KC_Jones said:



    Do not obsess over the pressure. The 0-30 psi gauge on the boiler will most likely never move. Steam heating wants as close to zero pressure as possible. Pressure, honestly, means problems. Could be the common oversized boiler, to bad piping, lack of venting. Pressure is bad and you don't want it.

    Thanks, my concern is mostly that the pigtail could be clogged and thus the pressuretrol would not be working. I agree that the pressure should be low, and I hope it is. Good to learn that the total lack of movement on my gauge might be normal but I suppose I won't know unless I remove the pigtail and check.

    Adding a low pressure gauge while I'm at it sounds like a good idea...

    Here's a question, if the system is running properly will the pressuretrol kick in to control things or is the pressuretrol more of an emergency device, operating only in exceptional situations (i.e. the boiler getting out of control)?
  • JUGHNE
    JUGHNE Member Posts: 11,062
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    In an ideal system the tstat does the controling.

    But in the real world the pressure control does the cycling on most systems IMO.

    If pipe sizes are large enough, main air venting ideal, boiler not oversized and the heat loss matching the boiler output then no cycling needed.
    roberts
  • Don_175
    Don_175 Member Posts: 126
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    roberts said:

    KC_Jones said:



    Do not obsess over the pressure. The 0-30 psi gauge on the boiler will most likely never move. Steam heating wants as close to zero pressure as possible. Pressure, honestly, means problems. Could be the common oversized boiler, to bad piping, lack of venting. Pressure is bad and you don't want it.

    Thanks, my concern is mostly that the pigtail could be clogged and thus the pressuretrol would not be working. I agree that the pressure should be low, and I hope it is. Good to learn that the total lack of movement on my gauge might be normal but I suppose I won't know unless I remove the pigtail and check.

    Adding a low pressure gauge while I'm at it sounds like a good idea...

    Here's a question, if the system is running properly will the pressuretrol kick in to control things or is the pressuretrol more of an emergency device, operating only in exceptional situations (i.e. the boiler getting out of control)?
    My new boiler never cycles with the pressuretrol (that I've seen). The max pressure I've ever seen is around 1.2 psi and pressuretrol cutout is 1.5. If your boiler is oversized, you may see it cycle vis the pressuretrol. Or if you don't have enough main venting.
  • roberts
    roberts Member Posts: 32
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    My new boiler never cycles with the pressuretrol (that I've seen).


    That leads to a question, how would you know if it was? I guess you just have to see if the boiler shuts down while the thermostat is still calling for heat? Would be nice if the boiler somehow logged this sort of thing...
  • KC_Jones
    KC_Jones Member Posts: 5,739
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    roberts said:

    My new boiler never cycles with the pressuretrol (that I've seen).


    That leads to a question, how would you know if it was? I guess you just have to see if the boiler shuts down while the thermostat is still calling for heat? Would be nice if the boiler somehow logged this sort of thing...
    For most people, you must watch it to know. I watched mine a few times to know it doesn't cycle on pressure ever and I was fine with that. I will usually observe a few cycles each year when I do my basic maintenance just to make sure it's all still running as expected. I also use my king valves to build pressure to check the pressure safeties so I know they are working.

    There are varying opinions on the pressutrol or vaporstat as operating controls versus safeties. I am on the safeties side. They should only operate when things are "out of hand" for some reason.

    There is also the discussion about boiler sizing, I and a few others feel the classic method is still over sizing the boiler, and many installers go beyond that which is just ridiculous and contributes to steam getting a bad name.

    Here is a great article about taking a different look at boiler sizing, and it doesn't get nearly enough attention if you ask me.

    https://heatinghelp.com/systems-help-center/taking-another-look-at-steam-boiler-sizing-methods/
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    roberts
  • roberts
    roberts Member Posts: 32
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    This is my first winter in the house, and the boiler is from 2018, so if it's oversized (not really sure yet either way) I think I'll probably have to live with it for a while, lol.

    That's also interesting about using the king valves to test things. Looks like I don't actually have king valves in my setup. I see no valves on the main lines.
  • Don_175
    Don_175 Member Posts: 126
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    roberts said:

    My new boiler never cycles with the pressuretrol (that I've seen).


    That leads to a question, how would you know if it was? I guess you just have to see if the boiler shuts down while the thermostat is still calling for heat? Would be nice if the boiler somehow logged this sort of thing...
    I have been in basement a couple times when boiler has really been steaming for a while. and temp is getting close to what thermostat is set for. Boiler will shut off when thermostat is satisfied but pressure is not high enough to trip pressuretrol. I think you can also tell by just listening for when boiler shuts off. At that point, check thermostat. Is it still calling for heat? Once my boiler shuts off, it typically doesn't run for another hour or so. I would think if pressuretrol had tripped, it would come back on after a few minutes once pressure dropped below pressuretrol cut in.
    robertsJUGHNE
  • mattmia2
    mattmia2 Member Posts: 9,660
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    You could get a pressure gauge with max/min pointers on it so it logs the highest pressure it has seen and compare that to the cutout of the pressuretrol
    roberts
  • roberts
    roberts Member Posts: 32
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    mattmia2 said:

    You could get a pressure gauge with max/min pointers on it so it logs the highest pressure it has seen and compare that to the cutout of the pressuretrol

    That's an interesting idea. Feels like someone in this group must already have a source on a good low-pressure gauge for this?

    Here's one with a decent range, but no max needle:
    https://www.supplyhouse.com/Winters-Instruments-PLP304-2-1-2-PLP-Steel-Low-Pressure-Gauge-1-4-Bottom-NPT-w-Brass-Internals-0-100WC