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Pressuretrol settings. Cut in @ 3 lbs. Diff @ 2 lbs. Thoughts ?

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Comments

  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    That means it won't cut out until 5psi (if it's even accurate). That's quite high.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    More importantly, if this is wrong, why would it have been set this way?

    Single pipe, 60 ft main loop, Gorton #1 main vent, rads with Gorton D

  • neilc
    neilc Member Posts: 2,854

    some folks don't know to run as low as they go,

    this is resi heat? you're not making beer or anything specail, are you?

    known to beat dead horses
  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    Respectfully, Coach (and I love that username by the way, Bad News Bears reference), you keep asking "why would someone do this" for things that are wrong. People do wrong things, let it go.

    OK the reason people often did that was to lessen "short cycling" which they saw as undesirable. But what it causes is needless fuel burning to raise the pressure way way higher than it needs to be.

    Try 1 cut-in and 1 diff

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

    delcrossvLRCCBJPRR
  • 109A_5
    109A_5 Member Posts: 1,670

    Hello CoachBoilermaker,

    Why does anyone do anything wrong ? Boiler installers don't bother to skim new boilers, wrong near boiler piping, the list is long.

    The thing is, if your boiler is well matched to the radiation the only real purpose for the Pressuretrol or like device is safety. My Pressuretrol never trips, the system never go over 2" WC (or 1.2 Oz.) so it does not really matter where the Pressuretrol is at.

    However when you get into oversized boilers, TRVs or someone runs around the house and shuts off half of the radiator valves there needs to be a safety pressure limit besides the relief valve.

    The other thing the Pressuretrol does, is if the system gets flooded, the pressure from the height of the water will shut off the burner.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    TKPK
  • Jamie Hall
    Jamie Hall Member Posts: 24,856

    Eek. That pressure setting will trash your vents… try setting both scales to 1. However, that unit is old enough that it may not be all that accurate, so it might not be a bad idea to install a good low pressure gauge on the system — you can do it on the same pigtail with a T, a couple (maybe 4) close nipples, and two 90 elbows.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    ethicalpauldelcrossvPEvans
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    Yes, glad you enjoyed the Walter Matthau reference. Coach Buttermaker. However, on this forum, I am no coach, I am the clueless bench-warmer!

    ethicalpaul
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    Someone set it there for a reason. Might not be wise to mess with it. Maybe I'll drop it by 1 and see what happens? I'll try to learn how to set it on YouTube, but this is a very old unit.

    Yes, maybe the boiler is overpowered.

    My calculated EDR is 220 sq.ft and 53k BTU

    The General Motors Delco DB-4S oil boiler is a relatively older model, and detailed specifications might vary depending on its exact year and configuration. However, for a typical Delco DB series oil boiler, the BTU rating is usually in the range of 100,000 to 150,000 BTU/hr, depending on the specific unit and its setup.

  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    Do you have a low-pressure gauge on Cedric, @Jamie Hall ? Or is that just what the vaporstat is set to? I would bet the whole house gets plenty of steam at way less than 4 ounces.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    Can you explain this? I get that it's wrong, but what they were compensating for. Pressure would hit limit too early because why? How does oversized boiler play into this? Explain like I am 5.

    Seems low risk to set it back to 1 & 1. Worst case, rads don't get hot?

  • KC_Jones
    KC_Jones Member Posts: 5,840

    Based on what we see around here, they are compensating for a complete lack of knowledge on getting the system to perform properly.

    As an aside, it is a safety device, with a properly operating system, and a properly sized boiler it should essentially never activate. The boiler should just heat the house and you are good.

    If it's working correctly, and you are hitting that limit at all, you can be fairly certain that boiler is massively oversized.

    2014 Weil Mclain EG-40
    EcoSteam ES-20 Advanced Boiler Control
    Boiler pictures updated 2/21/15
    LRCCBJ
  • delcrossv
    delcrossv Member Posts: 1,338
    edited November 14

    A misguided assumption that higher pressure steam moves faster- it doesn't. So, rather than fixing venting, they just say Hey! Let's crank up the pressure. 🙄

    E.G.: 200' of 3 inch main in a 4 flat I service. Whole thing heats fine on 3 OUNCES of pressure. How, you ask? Adequate main venting.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    LRCCBJ
  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    Pressure would hit limit too early because why? How does oversized boiler play into this? Explain like I am 5.

    The boiler makes a fixed amount of steam every given time period, depending on its size rating. Steam has about 1700 times the volume of water so the steam starts to create pressure in the boiler.

    The pipes carry the steam to the radiators (pushing the air out as it goes), where heat is…radiated…causing the steam to lose its latent energy and return to liquid state, and return to 1/1700 the volume it had before.

    So if the radiation in the house (all the radiators) can't condense steam fast enough, pressure will build in the system.

    This pressure is unnecessary, and can become dangerous, so there are a couple safeties on the boiler to prevent this pressure buildup.

    One is your pressuretrol, which "cuts out" the boiler (shuts it off) when the pressure gets to your "cut in" setting plus your "differential" setting. 1 psi is way more than enough pressure for steam to move through the system (about 1/27th that is all that is needed, but it's hard to create a safety device that is this accurate cheaply, so we get Pressuretrols which only activate around 2 psi).

    My thinking is there is no reason in the world to be burning fuel when the system gets into this state of "too much steam", so in my system, if I get up to about 2 ounces per sq inch, then my boiler shuts down for about 10 minutes to let the radiators send their heat into my rooms.

    The pressuretrol is simpler than this, and it will let the boiler run again when the pressure gets down to about the "cut in" point.

    The important thing to know is the pressuretrol does not "set" the pressure in the system, it simply acts as a pressure limit for the system. As @KC_Jones said, a well-sized system doesn't hit this limit very often, but well-sized systems are rare.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

    LRCCBJTKPK
  • Pumpguy
    Pumpguy Member Posts: 698

    I like @ethicalpaul's post.

    I would guess your pressuretrol's settings were set on the premise "if a little is good, more is better". This might apply to cookies or jelly beans, but is totally wrong for a building's heat steam heating system.

    Dennis Pataki. Former Service Manager and Heating Pump Product Manager for Nash Engineering Company. Phone: 1-888 853 9963
    Website: www.nashjenningspumps.com

    The first step in solving any problem is TO IDENTIFY THE PROBLEM.
    ethicalpauldelcrossvbburdLRCCBJ
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    Here is my best guess.
    Old boiler is probably oversized. (EDR is 52k BTU)
    Main vent is undersized (Gorton #1 for 60 ft main)
    Pressuretrol set at 1 would stop the boiler
    So, they raised it to 3 to stop the short cycling?

  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    What is the correct solution for short cycling boiler (and leaving pressure at 1) ?

  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    if it's oil, an oil technician might be able to down-fire it.

    If it's a gas atmospheric, you can lower the gas pressure a little, otherwise just let it cycle.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,380

    Make less steam. How do you make less steam? is your next question right?

    A smaller fire will make less steam. How do you make a smaller fire is your next question Right?

    Use less fuel. How do i do that is your next question Right?

    This is the one that is going to stop you in your tracks. because it costs $$$$

    Get a smaller boiler!.

    There is no answer to this series of questions that end with a $25.00 DIY fix. Sorry Coach 😫

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    bburdPC7060LRCCBJ
  • 109A_5
    109A_5 Member Posts: 1,670
    edited November 15

    Hello CoachBoilermaker,

    Personally I think the answer is quite simple. Once the system is at the point where the pressure is rising significantly the radiators can't condense the steam at the same rate as the boiler is producing it. Pipes are hot and the radiators are hot. So shut off the boiler (Pressuretrol, Vaporstat or your favorite low pressure switch) then the pressure will drop quickly, and once the differential of the pressure switch is satisfied the boiler will restart, and the short cycling will begin until the thermostat is satisfied. On-Off-On-Off-On-Off, seems silly, right ? So just turn up the allowable pressure setting. No don't, do this.

    The way I see it, the first time the trip (or Cut-Out) pressure is reached, maybe 8 Oz. (13.8" WC) or less, the boiler gets shut off, then delay the restart with a timer maybe 5 to 10 minutes. So no more crazy pressure, no more short cycles. There are other Electrical / Electronic ways, like controlling the situation by limiting the fill time of the furthest radiator from the boiler then shut down the boiler and then delay the restart.

    A timer is reasonably inexpensive and easy to install. Something like this is wired in series with the pressure switch circuit.

    https://www.supplyhouse.com/ICM-Controls-ICM203FB-ICM203F-Delay-on-Break-Timer-6-Wire-Leads-03-10-Minute-Knob-Adjust-Delay

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    LRCCBJ
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    The boiler is 80 years old. I doubt any tech has a clue how to adjust it.

    ethicalpaulLRCCBJ
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    Replace it for $20k or I can just ignore it and leave it at 3lbs.

  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    I agree that it was set at 3lbs for a reason. Boiler is 100-175k BTU. My measured EDR is 54k BTU. So, it was probably short cycling. Why is it bad to set it at 3lbs again? I assume it's been set this way for upwards of 80 years. What's the problem again?

  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    you tell us! If you don’t have any problems, then why is this thread here? 😂

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

    delcrossvLRCCBJPRR
  • Jamie Hall
    Jamie Hall Member Posts: 24,856

    Which problem? Wasted fuel? Damage to vents? Just off the top of my head. Just because it was working doesn't always mean it was working as well as it could be…

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347
    edited November 15

    To recap, oversized boiler will create excess steam and raise pressure.

    I guess it comes down to 3 choices:

    1. Replace boiler for $20k
    2. Short cycle boiler at 1 lb. (longer to heat up)
    3. Raise pressure to 3 lbs.

    How does allowing system to operate under higher pressure waste fuel compared to short cycling?

    For the millions of homes running an oversized boiler, which lesser evil is preferred, short cycling or high pressure?

  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    Cycling on pressure doesn’t make it take longer. It just saves fuel

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

    CLambGGross
  • Jamie Hall
    Jamie Hall Member Posts: 24,856

    As @ethicalpaul said, cycling on pressure won't make it take longer to heat the house — the radiation is doing all it can on the steam, which is still there, and that's what's heating the house. The extra fuel burned when the system should be cycled off so the system can catch up is just wasted.

    Much the lesser evil is cycling. Cycling on proper pressure saves fuel and prolongs the life of all the elements in the system. What's not to like?

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    bburd
  • 109A_5
    109A_5 Member Posts: 1,670

    Hello CoachBoilermaker,

    Pressuretrol settings. Cut in @ 3 lbs. Diff @ 2 lbs. Thoughts ?

    At least at the start of this thread the 'Cut out' or shutting the burner off pressure is actually 5 Lbs. not 3 Lbs., since 3 + 2 = 5. The turn back on 'when less than' pressure or 'Cut in' is 3 Lbs. Has the actual system pressure been monitored with a proper working Gage ? Why pay to make needless pressure or hyper cycle the equipment ?

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,380

    More energy is needed to make 5 PSI steam then 2 PSI steam. The oil burner must operate fonge to make 5 psi steam. if you stop the burner from operating when you have 2 PSI steam then you are not burning any oil. Now that you have 2 PSI in the steam boiler and the burner is off, you can let that steam pressure go to the radiators as long as the vents get the air out of the way. Of course that 2 PSI steam will find its way to some place to give off that heat and condense, resulting in a pressure drop that will bring the burner back on. but that burner off cycle is saving on fuel cost. If you left he burner on and raised the pressure to 5 PSI, that will not get the radiator to heat any faster and that higher pressure steam will not heat that room any faster. All that higher pressure steam did was use up more fuel… it did not heat the radiator any faster or heat the room any quicker. All that higher pressure did was to use more fuel with no actual benefit to comfort.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    delcrossvLRCCBJ
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    This finally clicked. Oversized boiler will fill rads and keep going. Pressure rises. You are at rad capacity. Might as well turn off boiler until rads empty and condensate allows pressure to drop. Correct?

    In that case, why is pressuretrol even adjustable? Why not hard set it to 1 & 1 ? If sized correctly, it will never cut out. And if oversized, might as well short cycle and save fuel. Correct?

    ethicalpaul
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    No, the system pressure has not been read. There is only one gauge 0-30 and it says broken on the face

  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    Thanks for reinforcing. My question above. Why is pressuretrol adjustable in the first place?

  • Jamie Hall
    Jamie Hall Member Posts: 24,856

    A number of possible reasons… first, not all systems operate well at a maximum pressure of 1.5 to 2 pounds. Vapour systems, for instance, get unhappy at anything over half a pound (so they use a similar but more sensitive device called a vapourstat). Many larger systems will have two or even sometimes three pressuretrols. One — likely a vapourstat again — for system cycle control. One, set higher, as a safety control. And some have a third, often manual reset, as a further safety control set significantly higher.

    Then some steam systems are used with some types of air handlers or unit heaters which need higher pressure. Others (such as breweries) run higher pressures because the need higher temperatures.

    And so on…

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ethicalpaul
    ethicalpaul Member Posts: 6,666

    In that case, why is pressuretrol even adjustable? Why not hard set it to 1 & 1 ? If sized correctly, it will never cut out. And if oversized, might as well short cycle and save fuel. Correct?

    For residences, they could be sold hard set. But there are some commercial uses where they want or need more pressure.

    The devices are so poorly calibrated though, it is very hard to even get them to cut out when they should. They shouldn't be relied on to limit to reasonable pressure. It's far better to size a new boiler appropriately so that the pressuretrol rarely comes into play.

    NJ Steam Homeowner.
    Free NJ and remote steam advice: https://heatinghelp.com/find-a-contractor/detail/new-jersey-steam-help/
    See my sight glass boiler videos: https://bit.ly/3sZW1el

    delcrossv
  • delcrossv
    delcrossv Member Posts: 1,338

    Or install a 0-3psi gauge and SEE what's going on.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
    TKPK
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,380

    really? Why is anything adjustable? I happen to like Bryer’s vanilla ice cream. So why would they make chocolate?

    Or any other flavor for that matter!
    The thermostat in my house is adjustable. The clock on my wall is adjustable.

    There is a speedometer on the dashboard of my car, and an accelerator pedal that allows me to pick where the needle on the speedometer goes whenever I drive it!

    There is one thing that I cannot adjust… . @CoachBoilermaker ability to ask questions that never cease to amaze me.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    LRCCBJdelcrossv
  • CoachBoilermaker
    CoachBoilermaker Member Posts: 347

    Everyone says to set it at 1 & 1.

    When do you vary from that?

  • Jamie Hall
    Jamie Hall Member Posts: 24,856

    If — and only if — you are dealing with an additive pressuretrol, 1 and 1 is fine — and it likely about as low as you can set it without having it come apart. That will give you a cutin pressure of 1 psig, and a cutout pressure of 2 psig.

    Now. Some pressuretrols — and all vapourstats — are subtractive, not additive. This means that the main scale setting is the cutout pressure, not the cutin. These must not be set with equal main scale and differential pressure. Why? Because in these the differential is subtracted from the main scale to give the cutin pressure, and thus if you set them equal the cutin pressure will be 0 psig.

    Problem. Both the cutout (main scale) setting and the differential are not all that precise. That is, they will vary from operation to operation by a small amount — for the sake of simplicity, let's say 5%. Now if on the particular operation the main scale is operating a little low — let's say 0.95 psig instead of 1 psig — and the differential is operating a little high — let's say 1.05 psi instead of 1 psi — the cutin won't occur until you get into a vacuum (in our example, minus 0.1 psig). Which is very likely to not happen. And, as a result, the device will never cut back in — and you will get cold and wonder what happened.

    My own rule with vapourstats and subtractive pressuretrols is that the differential should never be set to more than half the main scale setting. This is ample differential to prevent real short-cycling, but enough margin from 0 psig to ensure that the boiler will drop to the cutin.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • 109A_5
    109A_5 Member Posts: 1,670

    " When do you vary from that? "

    Hopefully never, at least with residential steam heat, you don't need the pressure, why pay for it. Get a functioning Gage or two on the system and see what the system is really doing.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System