Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Boiler short cylcing on Low Water Cut Off

Old boiler was replaced with new one the same capacity, I wasn't there at the installation and near boiler piping was done wrong see this tread <a href="http://www.heatinghelp.com/forum-thread/145113/One-riser-or-two-risers">http://www.heatinghelp.com/forum-thread/145113/One-riser-or-two-risers</a>

However for a week everything was more or less ok.

Now, a week later it short cycling not on pressure but on low water cut off.

In addition to that or may because of that, after boiler goes off after initial long cycle due to low water cut off, and comes on all my basement radiators, those which are below mains start hammering like crazy.

all radiators that are above the mains, on first and second floor work fine.

The system is a single pipe steam and I don't know if the new boiler was skimmed at all, and I am not a pro and could not find the skimming port on this boiler anyway.

While I am trying to make them redo the piping (and make sure they do skim the boiler this time) can anything be done in a meanwhile to get rid of the water hammer.

Please help





Thanks
«1

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    Sounds as if...

    your nice soggy steam is getting into those basement radiators -- and not getting back out.  This will happily lower your water level, hence the LWCO problem, and also make your nice banging.



    Question is: how is the water supposed to get out of those radiators and back to the boiler?  If they are below the main, are there drips back to a wet return from them?  If not, how then?  A sketch might help... or a good verbal description.



    Also, have you double checked your pressure?  If it is a bit high, could the condensate be backing up into those radiators as the pressure rises?  That would do it nicely, too...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • NY_Hammer
    NY_Hammer Member Posts: 65
    each of those basement radiators has a drip

    to wet return line.

    the worst one, newly added and closest to the boiler.

    Pressure is a bit high yet, if boiler doesn't go off by the water cut off, it goes up to 4psi.



    I purchased a vaporstat to replace pressuretrol the boiler came with but not installed yet.

     thanks for your help
  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    I'm not a gambling man...

    but I would give you odds that those 4 psi are backing condensate out of the boiler and into those radiators.  4 psi will raise water about 7 feet...



    Try 1.5 psi... or less!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • BobC
    BobC Member Posts: 5,473
    Too high

    That pressure is much to high, install the vaporstat and set the cutout to 1 PSI for a start; yu will probably be able to ho lower.



    If you look at the boiler manual they should specify a skim tapping, get a nipple and full port valve installed and skim that boiler.



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • NY_Hammer
    NY_Hammer Member Posts: 65
    nope

    Tried vaporstat started with 10oz. Went off within a minute.

    Tried up at 16 the same.



    Put back pressuretrol and lowered the pressure but with the same results.



    Boiler manual doesn't show skimming port.
  • MTC
    MTC Member Posts: 217
    When you say

    it went off within a minute after installing the vaporstat, was it going off on LWCO, or pressure?



    If pressure, you have some serious venting issues. There's no way you should be building that kind of pressure anywhere near that fast.
  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    edited February 2013
    That's not the vapourstat's problem

    That's a venting problem.  If you can build enough pressure to trip a vapourstat in one minute -- or even in 15 minutes -- your venting just has to be woefully inadequate.  Either that or your king valves on the risers are closed.



    To be blunt, it sounds as though this system is a mess.  Start back at square one and check all the basics and all of the piping and find out where your problems are and fix them.  Don't assume ANYTHING.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • NY_Hammer
    NY_Hammer Member Posts: 65
    The problem is

    The radiators are venting fine, I can hear it and they all are hot.

    And the fact that the same system was working fine a month ago before the boiler was replaced, even with the wrong near boiler piping.

    So the vents on my mains are still the same and working fine, I checked, the vents on the radiators are also working fine I checked.

    Actually I replaced  few of them with brand new HOFFMANS A1ajastables.

    And they all wide open set to #6.





    I am completely frustrated and lost now ...
  • NY_Hammer
    NY_Hammer Member Posts: 65
    edited February 2013
    what are king valves on the risers?

    wand which risers? Boiler risers or risers from mains to radiators?



    I don't think I have any of those.





    EDIT:

    I don not have those valves. As you can see from these pictures:

    http://www.heatinghelp.com/forum-thread/145113/One-riser-or-two-risers
  • pipeking
    pipeking Member Posts: 252
    edited February 2013
    i would have to say

    venting, the boiler should not start to build pressure until all the raditors r getting hot. so either the main is water loged, or the venting need to be increased. i know u said that your main vents r working but the prolly r not sized right, u can't have to much main venting!

    THIS IS AN EDIT, i went and looked at your other thread and seen your pics. well i have to say that UNTIL U GET THE OTHER BOILER RISER HOOKED UP TO THE HEADER (and not caped off), u r sure to have consistent problems. it would be fair to say that the steam is not exiting the boiler fast enough (cuz only 1 riser is being used) so pressure builds. it's an easy fix, with minamal pipe and fitting.
  • BobC
    BobC Member Posts: 5,473
    Has the boiler been skimmed?

    New boilers have to be skimmed to remove the oils as well as the crud that comes down from the mains after they get banged around during the install. When that stuff gets into the boiler it can cause an unstable water line and that can trip the LWCO.



    Did they look at the volume of air in the mains and run the calculations to make sure the main vents were adequately sized? You want to vent the mains fast and the radiators slowly for best performance. Slow venting will raise pressure fast as will a boiler that is to big for the system. If your building pressure very quickly it can mean the main vents are too small, the boiler may not be properly piped, or there may be blockage some where in the pipes.



    Has reducing the pressure helped the basement radiators as far as the water hammer goes?



    If the system was fine before the new boiler was installed something changed with that install. Post some pictures of the boiler and the piping around it so we can see what might be going on.



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • NY_Hammer
    NY_Hammer Member Posts: 65
    Not sure

    Not sure if it was skimmed. As I said I wasn't there when they installed it.

    Here is the link to the boiler manual

    http://www.newyorkerboiler.com/pdf/104460-02%20%28CGS-A%29%20w.pdf

    I could not find any mention of the skimming port. All tapping described on page 6 and there is no mention of it.

    Generally can I skim from the lower connector of sight glass











    ?
  • BobC
    BobC Member Posts: 5,473
    Up in the steam area

    Skimming should be done from a port that is up in the steam area of the boiler. A large tapping is best but you'll have to use what you have. You could use the pressure relief tapping by installing a T at that spot and putting the safety on the top tapping and then a nipple and a cap or full port valve on the open side of the T. If that is not viable then you could come off the top tapping for the sight glass.



    Skimming should be done slowly, you want to trickle the water out of a skim port slow enough that it takes a couple of hour to fill a 5 gallon bucket.



    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • NY_Hammer
    NY_Hammer Member Posts: 65
    Are you talking about

    Are you talking about so called cold skimming?

    with boiler off and just by slowly  raising water level until the water start coming out of this skimming port?





    Thanks again.
  • MTC
    MTC Member Posts: 217
    Yes

    Cold skimming, if you want to call it that.



    If possible, find a high up port to use, not the pressure relief valve. You don't want the water level to hit the top of the chamber inside, or it will grab onto a lot of the oils. Find something above water level, like the top sight glass port, if you have to.
  • Jamie Hall
    Jamie Hall Member Posts: 22,947
    The comment about king valves

    was a feeble attempt at humour.  Disregard...



    However.  Unless there is a serious restriction (like really serious) in the mains, a boiler on a heating system simply will not build pressure beyond a couple of ounces until virtually all, if not all, the vents are closed.



    It is possible that the not to spec near boiler piping is part of the problem -- but as I noted, 4 pounds will push water a long way up, never mind steam, and since you say the radiators are heating and not banging it isn't likely that large amounts of water are getting into the mains -- although it is very likely that some is.



    As I said before, go back to square one.  Start at the boiler, and see where the steam is going (and the air!) and see if you can find a restriction of some kind.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • NY_Hammer
    NY_Hammer Member Posts: 65
    The verdict

    here are my thoughts:



    There are two main factors causing the problem:

    1. Wrong near boiler piping

    a. capped second riser

    b. 2" header instead of minimum 3" recommended by the manufacturer

    c. 2" riser from the header up instead of minimum 3" recommended by the manufacturer.

    d. Less than 24" A dimention, and I am not even talking about top of the boiler to header, but from the middle of the glass to the header. It's still about 23" less that recommended minimum.



    2. After installation of new boiler it was not skimmed at all.





    So the way I understand it steam doesn't leave boiler upward quick enough so the pressure build very quickly and actually pushes water down into the return lines, hence lower water level causing Low Water Cut Off to shot the boiler off and flooding return lines in the process.



    This would explain everything, short cycling on low water level and banging in basement low located radiators.





    Anything I missed? LOL







      
  • ALIGA
    ALIGA Member Posts: 194
    the only thing missing is

    the damn installer. any luck getting a hold of him?
  • MTC
    MTC Member Posts: 217
    I'm not gonna say it ain't possible,

    But I'd be VERY surprised if you were managing to build a pound of pressure due to one riser instead of two and too small near boiler piping. I could see if you were kicking out at a few oz, but not a pound.



    I don't think you ever answered if the boiler is shutting down b/c it reaches vaporstat setting, or if its still LWCO after installing vaporstat? If it switched to the vaporstat and you're no longer going out on LWCO, then you're fine. You were operating your system at too high of pressure, problem solved (THAT problem, not the rest of them...)



    If you are building a pound of pressure in minute, even with all those near boiler problems, there has to be a venting problem. I know you said all was working fine before the boiler install, but think about it a bit.



    You MASSIVELY increased the velocity of steam exiting the boiler with those piping problems. Think about what other delicious things might be flying down those pipes and heading for your vents with that increased velocity? You could have smashed your working vents to smitherines with water, rust, mud, who knows what all is in the system.



    An open 2" pipe at only 1oz of pressure will move a LOT of air/steam. I'm just not buying that the near boiler piping could cause a pound of pressure to build up that fast. There has to be venting issues.



    Try removing one or more of your main vents, then run the system, and see what you get. Just don't stick your hand over the open hole to see if its working, unless you like taking trips to the ER.
  • NY_Hammer
    NY_Hammer Member Posts: 65
    It was shutting down on vaportsat

    for the very short time I had vaporstat installed.



    May be it was more than one minute but still it was short time.

    I will definitely look at the vents but after the piping ans skimming will be done.

    For now, I can hear vents on mains (I have two mains) working. The same on all radiators.

    Water in the boiler is very dirty, and has oil in in.

    When I installed vaporstat and reinstalled pressuretrol I had to clean the ponytail every time. Not that it was clogged but there was a lot of dirt.



    etc

     
  • NY_Hammer
    NY_Hammer Member Posts: 65
    This Friday

    installer is gonna come and fix the piping and other installation problems.

    This time I am gonna be around to make sure they doing it the right way.



    Hope it will help.

    If problems remain I will look at the venting.
  • MTC
    MTC Member Posts: 217
    Skimming and such are def good things to do

    and you really need to fix that near boiler piping. All of that is a given.



    But you were operating at way too high of pressure before. Just because it was technically working doesn't mean it was working right. If you let the boiler run long enough to build that much pressure, inadequate venting will get the job done, but not well.



    BTW, hearing the vents working is usually also a sign of underventing or failing vents. You don't really want to hear them.



    The pigtail was filled with dirty water, you mean? Or chunks of debris? It will fill with water, its supposed to, and if your water is dirty, well, that's what will happen. Make sure when you're cleaning them out that you prime them again (fill up the loop with a little water). If you don't, you're eliminating the protection that they offer.



    Try the removed main vent test, with the vaporstat, or with the pressuretrol turned way down. See if it cuts out. That will answer the venting question pretty handily.
  • pipeking
    pipeking Member Posts: 252
    mtc

    DITTO!! that pretty much what i went to post, but then when i went to load it got erased, so i figured i write it again when i came back. but mtc did it for me!
  • MTC
    MTC Member Posts: 217
    Thanks,

    its good to hear I'm in company with the king :)
  • NY_Hammer
    NY_Hammer Member Posts: 65
    will do !!!

    just before th new boiler was installed I was using the vaporstat as well with pressure set to 1.5psi.



    Wasn't short cycling and got nice even heat throughout the house.

    I have 2 floors and a basement.. 14 rads on two floors and 4 in the basement.

    No water hammer, no failed vents. I check them quite often.

    Using mix of Hoffman 1a adjustables and Heat Timer Varivalves  adjustables.



    Basically was very happy with the system until got hit by Sandy and replaced the boiler.





    I will definitely will take another look at the venting and pressure after these guys are done fixing what they had to do in the first place. May be I will even make them to go with dropped header, to make sure I have dryer steam ...



    Will see





    Thanks for all your advices and help.
  • ALIGA
    ALIGA Member Posts: 194
    push for the dropped header

    do it right once.
  • Mattimp
    Mattimp Member Posts: 1
    Boiler is getting flooded

    I am having a problem on a job that we installed a 500,000 gas fired steam boiler it's going off on low water when boiler shuts down on pressure then all of a sudden all the water in the glass gauge is gone .... Near boiler piping is correct what could be my problem I delayed the automatic feeder
  • NY_Hammer
    NY_Hammer Member Posts: 65
    Saga continues

    the installers finally came this morning...

    After multiple calls to NYC Rapid Repairs program, detailed complains, sending photos and installation manual pdfs.

    Without the owner master plumber, just his "guys".

    Refused to repipe the system, ignoring the manual, saying this boiler doesn't need second supply riser just because they "know it" and done 30 installations and nobody complained. 

    They drain the boiler, like I done many times before, refused to skim it, saying "they never ever skimmed a boiler after installation".

    Right after that I called their company a joke.

    They all got pissed of and left. Now there is gonna be another meeting, Monday, with everybody present, NYC RRP supervisor, general contractor, master plumber and me.





    to be continued ...
  • NY_Hammer
    NY_Hammer Member Posts: 65
    edited February 2013
    I did check my mains

    well, you were right, they probably not venting properly.

    I have two mains, one short,  about 15' and it has NO valve.

    One long, about 36' and has Gorton #1 valve.





    I guess I would need to move Gorton #1 to the short main and install one Gorton #2 to the long one?



    The mains are 2", would this configuration be sufficient?



    Also what is the vertical size of Gorton #2? What's the opening above the main should be so I can put that valve there?



    Thank you
  • pipeking
    pipeking Member Posts: 252
    well....

     the best way to go about it is to take a calm approach, it can get very frustrating i know. so, get to know the installation manual, and have them install it to the mfr. specs. just explain to them that u called the mfr. and they will not warranty the boiler in the future if it does not have the near boiler piping they recommend. why a company will argue with a customer about mfr. recommendations shows bad character. but with that being said i have heard of 100s of bad installs thru that program, so all u can ask of them is to just install like it is in the manual,nothing more nothing less! good luck
  • ALIGA
    ALIGA Member Posts: 194
    even the calmest person will loose their patience when it comes to

    Incompetence.

    I guarantee after showing them the manual, they will say, well we have done it this way 100s of times, and it works.
  • MTC
    MTC Member Posts: 217
    edited February 2013
    Main vents

    15' of 2" has .345 cu ft of air, a gorton 1 vents .33CFM at 1oz, so probably close enough (I target 1 min at 1oz.)



    36' of 2" has .828 cu ft of air, a gorton 2 vents 1.1cfm at 1oz.



    This setup sounds good to me.



    Try to get your vents just after the last riser, and up 6" above mains if possible, to protect them from water hammer, etc.



    Gorton 2 is about 7" tall, and uses a 1/2" tapping or fitting, if that's what you were asking. If you're adding one, I'd put it in as a 3/4" if possible, then go up with a 3/4" short pipe (5" or so ideally) to a reducer,and put your vent in that. This gives you more options, should you want to do something different, add more vents, etc later.
  • NY_Hammer
    NY_Hammer Member Posts: 65
    they did already

    I showed them the manual and that's exactly what they said.

    We did it this way hundred times and nobody complained.
  • pipeking
    pipeking Member Posts: 252
    edited February 2013
    now

    it's time to tell them that u talked to the mfr and they said the only way that they will warranty your boiler in the future should something happen that it has to be installed as they show it in there manual. as that is the case with all mfr (not only boilers, it's the same as cars,appliances,swing sets,ect...)so that's nothing new.
  • RobG
    RobG Member Posts: 1,850
    edited February 2013
    What's the verdict?

    Any news?

    One other thing I noticed, that boiler requires 6" clearance from combustables. It looks like the bottom left is pretty tight to the wall. As well, I would check on the venting, it lookds pretty dubious to me.

    Rob
  • NY_Hammer
    NY_Hammer Member Posts: 65
    edited February 2013
    It was finally redone

    Not completely but I think good enough.



    could not push them to do dropped header, but the header is much higher now.

    It's about 24" above the top of the boiler and about 33" above the water line.

    The horizontal vent line is also supported now. Boiler was skimmed after installation.



    The other thing I had to agree is to keep 2" header instead of 3". Installation manual is not clear on that size, after much debate it was agreed that it actually recommend 2".

    Vertical take off recommended 3" but I guess it's ok to have it at 2".



    But as extras I have now king valve on that vertical take off, valve on the Hartford loop, and two additional drains, one on the return line before the valve and one after as recommended by Dan Holohan on his near boiler piping video

    http://www.heatinghelp.com/article/107/Steam-Heating/118/Steam-boiler-near-boiler-piping



    Here are updated pictures:



     
  • pipeking
    pipeking Member Posts: 252
    uhm....

    wow.
  • NY_Hammer
    NY_Hammer Member Posts: 65
    Meaning?

    That  WAW means good or bad? LOL



     
  • NY_Hammer
    NY_Hammer Member Posts: 65
    the shortest distance to the wall

    on the right side of the boiler is 8".
  • MTC
    MTC Member Posts: 217
    Seems like everything is functional

    in that setup, but def a bit odd. Lots of strange uses of 45s and such, and its a little "messy" of a piping layout to get around the flue, but seems to work.



    Not sure that there's any real problems, other than the header probably being undersized. But I'll let pipeking or someone else who does more actual near boiler piping chime in, as I could be missing some things. I mostly just maintain old systems :)



    Any report on the way the system is running so far?
This discussion has been closed.