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Hoffmann Differential Loop newb

GW
GW Member Posts: 4,605
I looked at a job yesterday, big ole boiler needs to go. It's has the Hoffmann Differential Loop. It does have a patch on it, one of those 'clam shell' clamps; would one still leave the Loop?

The water line is the highest i've ever seen on a residential boiler. There are loop seals--two mains and the loop seals are about the same height. I didn't measure the height but I'm guessing 4' or so. I'm guessing the water line is 5'.

How many inches above the loop seals might I want the new water line? Basement seems plenty tall.

I could go back and get more notes if anyone can help me make this less scary. And thank you for those that PM me here and there when i have steam questions. I am good with one pipe but never dealt with two pipe much. I told the older gent that I haven't done a two pipe with the Loop, and he is fine with that fact. he said he was (is) a PE.

Thanks, Gary

Gary Wilson
Wilson Services, Inc
Northampton, MA
[email protected]

Comments

  • Keep The Loop. Just watch Point W. Here you are:



    More info, especially on crossover traps. For those you need @Sailah, aka Peter The Great.
    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • Danny Scully
    Danny Scully Member Posts: 1,397
    @GW, with a modern Vaporstat, in theory, the loop isn't needed. I only say this because you're suggesting there is or may have been a leak in the differential loop. If the leak isn't repairable, then again, in theory, a Vaporstat is all you need. I do love these original devices, however, and if you could keep it, that would be great too. You would still need a Vaporstat though.
  • GW
    GW Member Posts: 4,605
    Thanks NESW, it's got the crossover traps. Are new traps hard to come by? I was reading a post on that.

    What am i looking for at Point W? I'm guessing the Loop stays in place.

    The loop seals will be above the new boiler's water line---I need to lower the loop seals i take it.

    Gary
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • GW
    GW Member Posts: 4,605

    @GW, with a modern Vaporstat, in theory, the loop isn't needed. I only say this because you're suggesting there is or may have been a leak in the differential loop. If the leak isn't repairable, then again, in theory, a Vaporstat is all you need. I do love these original devices, however, and if you could keep it, that would be great too. You would still need a Vaporstat though.

    Danny, I thought if the loop goes there's a bunch or re-do'ing going on. One could take the loop out and not get into too much trouble?

    Yes, a new vaporstat is easy enough.

    The leak looks like it's been holding well.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • GW
    GW Member Posts: 4,605

    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • GW
    GW Member Posts: 4,605
    well it was up and down
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Sailah
    Sailah Member Posts: 826

    Keep The Loop. Just watch Point W. Here you are:



    More info, especially on crossover traps. For those you need @Sailah, aka Peter The Great.

    Lol, I told my wife she needs to start referring to me like that....

    It's cold in the barn with this weather!
    Peter Owens
    SteamIQ
    MilanDCanucker
  • That's better:

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
    GW
  • Steamhead
    Steamhead Member Posts: 15,983
    The air vent on that Loop is way too small. We generally use at least one Gorton #2 on these systems. Remember, that's the only air vent in the entire system, and it does get steam if the Loop operates.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    New England SteamWorks
  • Jamie Hall
    Jamie Hall Member Posts: 21,091
    Beautiful. As has been said, keep the loop. And do put a much larger vent on it -- that old vent was OK with a slow firing coal boiler, but not with a modern boiler.

    Don't put ANY vents anywhere else on the system. If there are any, remove them.

    Also as has been said, you will need a vapourstat. The loop will trip at somewhere around 10 to 12 ounces, and you don't want it to do that if you can help it.

    The crossover traps are just like radiator traps. Sometimes bigger. They are essential! Barnes & Jones can get you replacement innards (or whole traps) if they aren't functioning.

    One of the beauties of the system is that with the loop operating, the pressure differential at a trap never goes over that 10 to 12 ounces -- and traps tend to last forever.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • GW
    GW Member Posts: 4,605
    edited September 2017
    Thanks Jamie so the new boiler would have a water line of about 24". The two Loop Seals are about 48". The old water line is out 60", very tall beast.

    Do I get some ugly cement blocks or chop the seals and lower them. If I lower the loop seals I can add ball valves and a way to flush out the wet return mains which run along the floor, I'm guessing 40 foot each. Maybe 50

    There is a rad with an air vent. Oddly, that rads trap is set up sending the return pipe into the wall.....not down into the floor. I am guessing the trap doesn't work when it is sideways.

    The house is a little packed, putting it nicely. The owner says there is one other radiator with an air vent as well, which I haven't seen yet.

    I sent off and initial quote, homeowner seems good to go. I said I need to go back to get more notes, information.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Danny Scully
    Danny Scully Member Posts: 1,397
    You'll want to build a false waterline @GW.
  • GW
    GW Member Posts: 4,605
    Don't worry about the goop in the wet mains ?
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Danny Scully
    Danny Scully Member Posts: 1,397
    edited September 2017
    No @GW, you should still address that. I guess now that I'm thinking it through a little further, lowering the loop seals is probably the same amount of work as adding a false waterline.
    GW
  • GW
    GW Member Posts: 4,605
    Cool, huh? I could drop a new radiator return into the wet return in the basement i guess.


    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Jamie Hall
    Jamie Hall Member Posts: 21,091
    Were it mine I'd drop the loop seals (and anything horizontals) to well below the new water line -- look all over the place! And add nice drains or at least Ts to flush them.

    I like that return going into the wall... sigh. Oh well. If you do drop the return directly into a wet return rather than a dry, then you would need a vent on that return line somewhere above the water line.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • ChrisJ
    ChrisJ Member Posts: 14,377
    MMM, dirty toilet brush touching hot radiator.

    That must smell nice.
    Single pipe quasi-vapor system. Typical operating pressure 0.14 - 0.43 oz. EcoSteam ES-20 Advanced Control for Residential Steam boilers. Rectorseal Steamaster water treatment
    GWMilanD
  • Jamie Hall
    Jamie Hall Member Posts: 21,091
    That should have been anything horizontal which was below the old waterline! I sometimes (often?) type faster than I think...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • GW
    GW Member Posts: 4,605
    Yes Jamie i knew what you meant.

    The horz wet ret is pretty close to the floor, I'm guessing a foot or so.

    I'll plan on lowering the loops seals and installing a means to flush with a hose.

    When I go back I'll get more notes.
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Sailah
    Sailah Member Posts: 826
    We make left hand right hand traps so the angle pattern isn't laying on its side like that.
    Peter Owens
    SteamIQ
  • GW
    GW Member Posts: 4,605
    Peter what's the model?

    Thanks, Gary
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • JUGHNE
    JUGHNE Member Posts: 10,561
    Is that an air vent on the lower part of the rad near the trap, in that picture?

    So Chris, how do you know the potty brush is dirty???
  • Sailah
    Sailah Member Posts: 826
    GW said:

    Peter what's the model?

    Thanks, Gary

    Hi Gary,

    Sorry for delay. That would be a 122RH (Right Hand), 1/2 x 1/2 NPT

    Attached pic

    Peter


    Peter Owens
    SteamIQ
  • GW
    GW Member Posts: 4,605
    Peter thanks, that's a pretty looking valve

    in my case, the orig installer just took a normal trap and spun it sideways, I presume that's not gonna vent well? Hence, the added air vent?

    You think i could get that valve installed in place of the 'normal' trap that's there now?

    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Sailah
    Sailah Member Posts: 826
    Well I can't speak in absolutes based on a picture but I can say that a normal trap won't work well because the element is sideways in condensate 100% of the time. So if anything it's probably venting too much and won't close. Ie blowing by.

    This is the correct trap for that configuration, right hand, but it's up to you to get the pipes aligned to where it will fit. Might take some moving of pipe to fit, not very good access I will admit.
    Peter Owens
    SteamIQ
  • GW
    GW Member Posts: 4,605
    Yes Ok i will cover that in my details if this guy pulls the trigger

    Is that you in the B&J Youtube videos?
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Sailah
    Sailah Member Posts: 826
    Why do I look different than you expected? ;)

    Yes that's me, unless you are seeing Danny in the videos. He's been there for 39 years and I'm turning 40 this March!
    Peter Owens
    SteamIQ
  • GW
    GW Member Posts: 4,605
    edited September 2017
    I can't see you, just you shirt sleeves and watch

    Hmmmm the full post didn't go in

    Anyway I was saying it sounds like a voice of a 40 year old and not a voice of a guy that's been there 39 years
    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • Sailah
    Sailah Member Posts: 826
    Yep that's me. I have face for radio B)
    Peter Owens
    SteamIQ
    GWNew England SteamWorks
  • GW said:

    Is that you in the B&J Youtube videos?

    What videos? Do share!

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    newenglandsteamworks.com
  • Sailah
    Sailah Member Posts: 826

    GW said:

    Is that you in the B&J Youtube videos?

    What videos? Do share!

    This was probably my favorite. Remember when that radiator exploded last year? I decided to turn on the steam in our lab and see how long I could stay in there. It just got really humid haha.

    https://youtu.be/X-ffmWA1fH0
    Peter Owens
    SteamIQ
    GW