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Radiator Balance/Boiler short cycling issue

mwoodjbmwoodjb Posts: 6Member
One pipe steam, additive pressuretrol. HELP.

Brief History: System has worked pretty well for years, after some work to balance it. This despite the fact that the Main vents were undersized (after two different plumbers told me nothing else could be done to replace the ancient ones because the thread size was too small for newer ones. I wondered then--I'm smarter now--and ticked.) Thinking back, probably not working as well the past few years--but not enough that we really noticed it.

This winter:

First, no heat at all on single digit day--despite boiler running non-stop. Had plumber in. Said not getting enough gas--check with PSE&G before he replaces boiler gas valve. PSE&G fixes it--condensation in the outside line had frozen. Said pressure good--probably better than before.

Second, next really cold snap, pretty similar symptoms. Called PSE&G first. Pressure checked out ok. Saw crud underneath and said boiler cracked--but it has not been losing water. Plumber comes for second opinion--no crack at bottom, tests for crack at top--all good. Checks pressure controls--badly clogged pigtail. He replaces it. Things much better, but radiators in stack (1st, 2nd, attic) farthest from boiler not heating.

Third, I do some research--maybe bad main vent. I take it for replacement and explain it's a hack, and I really would rather the right size--they give me Gorton #1 and parts to downsize threads. (Other main was same, I replaced it too with right size--#1.) Those 3 radiators still cold. So I research pressuretrols. Cut in was set at 2.5, inside dial at 2. (Additive) I lower cut-in to 0.5 and dial to 1. Better. Downstairs and most upstairs rooms are lovely. First floor rad gets heat--after an hour or more. 2nd floor takes 3-4. Nothing in the attic. This is in the morning. Boiler seems to be running constantly till it gets up to temp--at least every time I check. Later in day or evening I am less clear on--though attic rad got a teeny bit of heat last night before system went to night temp.

SO: I am thinking I need to get bigger vents on those radiators, but I want to know if I can just change them and leave the rest alone. Also wondering if I should have a #2 on the long main--though it does not have any risers off of it--and as near as I can tell the far radiators must come off a short end riser(s) which then goes over. And/or could something else be involved in the short cycling?



I can do pictures as needed.

Comments

  • Jamie HallJamie Hall Posts: 10,274Member
    Is it short cycling? You also say the boiler is running constantly? I'm confused.

    On the vents -- a Gorton #2 on the longer main wouldn't hurt...

    Have you tried a slower vent on the radiators on the 1st and 2nd floor in the stack that includes the attic? Or you might need a vent on the riser in the attic -- before the radiator -- to get steam up there quicker.

    Does that riser go up in or next to an outside wall?

    Are all the mains insulated?
    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • mwoodjbmwoodjb Posts: 6Member
    Thanks.

    I read something that said extreme short cycling is basically running continuously--but maybe not. I know it will run often to get it up to temp, but I would expect off times as the radiators cool and empty back to the boiler. I've checked when they are cooler and found the boiler running. I could just be missing the break. What would a "normal" cycle be for sub-freezing weather to raise the temp 8-10 degrees?

    Yes, risers in (and radiators on) outside wall. Mains are insulated.

    So you are suggesting I want a smaller vent on the 1st/2nd floors? Will that make them heat faster? (I thought I wanted to go the other way.)
  • Jamie HallJamie Hall Posts: 10,274Member
    To raise the temp 8 to 10 degrees? First place, that's way too much setback. Most folks find that anything much over 3 degrees on steam wastes fuel.

    But what would a "normal" cycle be for that much of a rise? Depends on so many variables -- the building, the size of the boiler, the size of the installed radiation... About all I can tell you on that is that it if it were a cold day it would take Cedric four to five hours to make that much gain. Maybe more. He is slightly oversize for the radiation, so that after about 45 minutes straight running he would be cycling on pressure about 45 seconds off and 5 minutes on until the thermostat was happy.

    On the vents. I'm thinking that in the absence of venting the riser, the first and second floor radiators are stealing steam from the attic radiator. All three are, perhaps, slower than they should be -- but that is as much a matter of main venting as anything else. Ideally, all the radiators would start getting hot pretty much at once. Never happens, but it should be close.

    Jamie



    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.



    Hoffman Equipped System (all original except boiler), Weil-Mclain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • mwoodjbmwoodjb Posts: 6Member
    "To raise the temp 8 to 10 degrees? First place, that's way too much setback. Most folks find that anything much over 3 degrees on steam wastes fuel."

    Really? I know too much makes it work too hard, but we do 60 degrees at night and 68 daytime. Is that so unusual? Or just bad with steam?

    And that helps--maybe I am worrying too much about that am running time. It is definitely not doing that during the day (since the recent problems and fixes.)

    Thanks again--this is helpful.
  • KC_JonesKC_Jones Posts: 4,093Member
    Said it many times on here, if you can actually drop 8 degrees overnight you have much bigger problems to worry about.

    And yes an 8 degree setback is excessive for any system IMHO, as said you shouldn’t be able to drop that much.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    https://www.facebook.com/media/set/?set=a.10202744301871904.1073741828.1330391881&type=1&l=c34ad6ee78
  • mwoodjbmwoodjb Posts: 6Member
    edited March 3
    KC_Jones said:

    Said it many times on here, if you can actually drop 8 degrees overnight you have much bigger problems to worry about.

    Like insulation (we are supposed to have some but I have questions about that), and ancient windows/storms?

    And I will reduce the setback. I like it on the cooler side for sleeping, but the wife will sure be happier in the morning...

  • FredFred Posts: 7,813Member
    How long are the mains and what diameter? A Gorton #1 will reasonable vent about 10, maybe 15 feet of 2" main properly. You may need one or more Gorton #2's on those mains, preferably a Barnes and Jones Big Mouth. And yes, an 8 degree setback is way too much set-back. 2 or 3 degrees would be best.
    As to your radiator vents, when we say larger or smaller radiator vents, we don't mean the tapping into the radiator. We mean a radiator vent that vents faster or less fast to balance the system. If the guy you had said the threads were too small for larger vents, he is correct but clearly he does not know steam if he suggests he can't change a radiator vent because the threads are too small.

    And no, short cycling is not that the boiler runs constantly. Short cycling means, during a normal heat cycle, the boiler runs for a normal period of time, maybe 15 or 20 minutes and then reaches a pressure cut-out and the Pressuretrol shuts the boiler down until the pressure drops, maybe 15 to 30 seconds and then starts up again and continues to do that until the thermostat is satisfied. It should to me like you don't have enough main venting, for starters and it takes too long for the steam to push all the air out of the mains so that steam can reach the furthest radiators. Once you get the main venting correct, then you can start to balance the radiators with faster or slower radiator vents or maybe use vents that are adjustable so that you can adjust them until you get each room the way you want them. In any case, stop the 8 degree setback.
  • nicholas bonham-carternicholas bonham-carter Posts: 7,817Member
    You can always turn the vent upside down in the bedroom, at night, and that will prevent steam from getting into that radiator, so making the room cooler, (you may need to flip it up again at 5am for your wife to wake up happy).—NBC
  • KC_JonesKC_Jones Posts: 4,093Member
    > @mwoodjb said:
    > Said it many times on here, if you can actually drop 8 degrees overnight you have much bigger problems to worry about.
    >
    > Like insulation (we are supposed to have some but I have questions about that), and ancient windows/storms?
    >
    > And I will reduce the setback. I like it on the cooler side for sleeping, but the wife will sure be happier in the morning...

    Air leaks are the biggest problem. Get a couple cans of spray foam and spend some time in your basement.
    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    https://www.facebook.com/media/set/?set=a.10202744301871904.1073741828.1330391881&type=1&l=c34ad6ee78
  • mwoodjbmwoodjb Posts: 6Member
    Fred said:

    How long are the mains and what diameter? A Gorton #1 will reasonable vent about 10, maybe 15 feet of 2" main properly. You may need one or more Gorton #2's on those mains, preferably a Barnes and Jones Big Mouth. And yes, an 8 degree setback is way too much set-back. 2 or 3 degrees would be best.
    As to your radiator vents, when we say larger or smaller radiator vents, we don't mean the tapping into the radiator. We mean a radiator vent that vents faster or less fast to balance the system. If the guy you had said the threads were too small for larger vents, he is correct but clearly he does not know steam if he suggests he can't change a radiator vent because the threads are too small.

    Mains are 2" Short run is about 22 feet with a couple of bends. Long one closer to 40--in a big "U" around basement. But no risers off the long one after about 20 feet. (Which may be odd in itself.)

    Also, when you say more than one vent--how does one do that with only one existing opening (where the old vent was)?

    And I get it about the radiator/main vent size of threads--I am very ticked that 2 plumbers told me it was impossible to replace the 1950's vents because the treads were too small.

    I was confused about sizing as in Gorton 4/5/6/C since someone above suggested a "slower" vent but I had been thinking I wanted faster--which I understand to be a larger size.
  • FredFred Posts: 7,813Member
    @mwoodjb
    - For two mains, that size, a Gorton #2 on each main will be fine. For the same money, though, you can get Barnes and jones big Mouths. They have about 2.5 times the venting capacity of the Gorton #2.
    - The longer main with no radiator run-outs after the first 20 feet is just an extension of the main that acts like a dry return to carry condensate back to the boiler. It is not necessary to push air out after the last radiator run-out so both mains can be treated as if they are both the same length.
    - If you needed to use multiple main vents, on a main with only one opening, you build what is called an antler that is made up of a few nipples, tees and elbows so that multiple vents can be added to the antler. You need at least a 1/2' opening to do that and a 3/4" opening is even better. 1/2" and 3/4" openings can vent far more air at 1 ounce of pressure than virtually any main vent so adding more vents speeds the evacuation of air up to the capacity of the opening in the main. In your case, with only 20 ft. of main, the equivalent of a Gorton #2 is fine.
    - Once you get those vents on the mains, then you can go around and change radiator vents, either larger (for faster venting, in cooler rooms) or smaller venting (in rooms that get to hot) so that all the rooms are balanced. Many of us like to use the Vent-rite #1 or the Hoffman #1A radiator vents as they are adjustable and make balancing easier by just turning a dial or the cap on those vents. That way you are not guessing what size you need for each radiator, like you will do with fixed vents.
  • mwoodjbmwoodjb Posts: 6Member
    Thank you! That is very clear and helpful!
  • SeanBeansSeanBeans Posts: 291Member
    @KC_Jones

    I was working at a house that a nice old blind lady owned.

    Before we left for the day she wanted us to make sure that her thermostat schedule was not disturbed. she had the daytime temp set to 74, and the night time (starting at 7pm) would be set to 42 degrees! Hahah

    32 degree setback,anyone?
  • KC_JonesKC_Jones Posts: 4,093Member
    SeanBeans said:

    @KC_Jones



    I was working at a house that a nice old blind lady owned.



    Before we left for the day she wanted us to make sure that her thermostat schedule was not disturbed. she had the daytime temp set to 74, and the night time (starting at 7pm) would be set to 42 degrees! Hahah



    32 degree setback,anyone?


    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    https://www.facebook.com/media/set/?set=a.10202744301871904.1073741828.1330391881&type=1&l=c34ad6ee78
  • gfrbrooklinegfrbrookline Posts: 369Member
    Does the boiler ever stop running during the day?
  • FredFred Posts: 7,813Member
    OMG What time was it set to recover to 74? I doubt that she would get down to 42 in a 6 or 8 hour window but I'm sure she has to recover 12 to 15 degrees.
  • SeanBeansSeanBeans Posts: 291Member
  • SuperTechSuperTech Posts: 938Member
    My question is did the old lady put the A/C system on at night in an attempt to get the house down to the desired temperature of 42 degrees?
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