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Boiler won't build pressure

EZPassGas
EZPassGas Member Posts: 16
in THE MAIN WALL
My Dunkirk PVSB-4D boiler will not make pressure. The only thing that shuts it down is 1) the LWCO after it's runs a while. Once the LWCO is triggered the boiler shuts off, the condensate returns and tells the LWCO everything is OK and the boiler fires back up. It continues to go thru that cycle until the 2) thermostat is satisfied. FYI the rads do warm up nicely.

I have a 3 psi gauge that doesn't move off 0 psi. Pigtail is clean, just cleaned it last week. I have two mains (9' and 11') both, both a vented by (2) Gorton #1. The mains feed 8 rads (4 on each main) and all rads use various sizes Gorton air eliminaters.

I thinking hole some were in the boiler but any other ideas would be appreciated

Comments

  • nicholas bonham-carter
    nicholas bonham-carter Member Posts: 8,578
    To check for a leak in the boiler, let the boiler cool while switched off, and then overfill it until you can feel the header getting cool. Let it sit for a couple of hours, and then check for leaks onto the floor.
    Your LWCO should not be activating frequently.—NBC
  • KC_Jones
    KC_Jones Member Posts: 5,840
    If the LWCO is shutting it down during a cycle that could indicate partially clogged return piping which is delaying the return of the condensate.

    Also keep in mind you don't want to build pressure, if you are building pressure and shutting down on the pressure safety that is actually a bad thing.

    It won't hurt to check for a leak as indicated by the above.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    ChrisJ
  • Jamie Hall
    Jamie Hall Member Posts: 24,852
    What @KC_Jones said.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,475
    Post a few pictures of the boiler and the piping around the boiler. Otherwise what @KC_Jones recomended
  • JUGHNE
    JUGHNE Member Posts: 11,276
    All of the above plus if you shut off the water feed valve, (obviously your LWCO is being constantly tested, It does shut the fire off....yes?) then when the boiler off on low water and the water returns and boiler starts again you have slow returns.

    If not enough water returns after maybe an hour, then you may be loosing water somewhere......boiling out of holes in cast iron boiler :s or better would be to have leaking return lines you can not see. :p
  • JUGHNE
    JUGHNE Member Posts: 11,276
    But, do you have a dreaded "Cycle guard" LWCO ??
  • EZPassGas
    EZPassGas Member Posts: 16
    The returns work good.... I think. Once the boiler shuts down, the water level is near the upper limit within 1min and all the way recovered in under 2
  • EZPassGas
    EZPassGas Member Posts: 16
    Also all my lines are above ground
  • Fred
    Fred Member Posts: 8,542
    How old is this boiler? Has any piping work been done since the last time the boiler was skimmed? It almost sounds like there are oils on the surface of the boiler water and the water is being pushed out into the wet returns. Does the water in the sight glass bounce a lot when the boiler is running?
    Or, as Jughne, it has a Cyclegard LWCO on it that shuts the boiler down at 20 minute intervals.
  • EZPassGas
    EZPassGas Member Posts: 16
    @EBEBRATT-Ed Not sure exactly what you want for pics but here's the boiler front
  • KC_Jones
    KC_Jones Member Posts: 5,840
    edited November 2017
    There is no functional reason for the LWCO to shut the boiler down under normal operation. Again if it's shutting it down during a cycle for a low water condition you either have slow returns or a leak.

    If it's shutting down for low water and then a couple minutes later the water returns enough for the boiler to fire up that is a slow return.

    Or as Fred said oils and it needs skimming.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
  • Fred
    Fred Member Posts: 8,542
    Is there an equalizer on that boiler? Is that the wet return that runs directly into that boiler? If it doesn't have an equalizer, it is most likely pushing water out into that wet return.
  • EZPassGas
    EZPassGas Member Posts: 16
    I'll send more pics of the Hartford Loop tomorrow but yes, I believe it has an equalizer. The the interesting thing about the LWCO is there is still 1/3 of the water in the sight glass when it cuts off. It never really gets "low". There is not much bounce in the water maybe a 1/2".
  • EZPassGas
    EZPassGas Member Posts: 16
    @Fred @EBEBRATT-Ed
    More pics
  • EZPassGas
    EZPassGas Member Posts: 16
    Pics
  • Fred
    Fred Member Posts: 8,542
    Actually, the boiler looks like it is plumbed pretty well, but now that I look at it a little closer, it looks like the LWCO may not be in the correct tapping. It looks to high and may well be the reason it shuts the boiler down with plenty of water in it. If you have the Owner's I&O manual, take a look at it and see where the LWCO should be located. If you are not using a lot of water, don't worry about the fact that you are not building pressure. That's a good thing. If it builds just enough to push steams to all of the radiators, that's all you need.
    JUGHNEMilanD
  • MilanD
    MilanD Member Posts: 1,160
    Yes, that McDonnel Miller LWCO is installed too high. Tapping is almost at the water line (maybe an inch below water line). Once the boiler steams, that whole water line zone is one big steam bubble zone, up and down a 2-3 inches.
  • Kahooli
    Kahooli Member Posts: 112
    I think you two are wrong about the LWCO. This is probably a remote probe version, and the probe is in a tapping under the burner panel at the air intake side. Easy to check - just take the panel off and look for the wire and probe on the left or rightmost section - probably right section.
  • Kahooli
    Kahooli Member Posts: 112
    MY own probe would behave this way when it was excessively dirty.
  • MilanD
    MilanD Member Posts: 1,160
    Kahooli said:

    I think you two are wrong about the LWCO. This is probably a remote probe version, and the probe is in a tapping under the burner panel at the air intake side. Easy to check - just take the panel off and look for the wire and probe on the left or rightmost section - probably right section.

    Quite possible. Manual shows 2 probes. OP pic shows McDonnel right there at the water line. Is this supposed to be water feed probe?

    If this is the case, clean the lower probe, per @Kahooli suggestion and you may fix the issue.
  • Fred
    Fred Member Posts: 8,542
    We need the OP to take a look at what he has. I still think that he may not have a remote probe or, if he does, it may be in the wrong tapping. If it consistently shuts the boiler down at 1/3 full. Seems too consistent to be a cleaning issue but, I suppose anything is possible.
  • EZPassGas
    EZPassGas Member Posts: 16
    Steam traveling to the radiator is not a problem. Everything heats up nice. Occasionally when it runs for a while (a few on/off cycles to satisfy the t-Stat)the big rad in the dinner room gets water in it and makes a sloshing sound.
  • Fred
    Fred Member Posts: 8,542
    I assume it is shutting down during a heating cycle because of the LWCO? Did you check to see if you have a remote LWCO probe and if it is in the right tapping. If you don't have a remote probe, that LWCO is in the wrong location.
    Check the pitch of that dinning room radiator. It has to be pitched so that condensate can return. Also make sure that dining room radiator supply valve is fully open or water can't return. If you have it partially closed to control the steam flow, you need to do that by using a radiator vent with a lower venting rate, not the supply valve.

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