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2 Pipe Counterflow System

JUGHNE
JUGHNE Member Posts: 9,765
Some questions, this is a NG HB Smith boiler GHB2-9-2, 245,000BTUH input/196,000 output.
Serial number is B82S ? Seems too short for SN. But would the year be 1982?

Original M&M LWCO has round handle blow down valve with the round hubs on water in/out ports.
(Pre 1995 IIRC). Probably has never been opened...obviously replacement time.
Understanding owner realizes that this is the singular LWCO and has concerns for safety issues. He is the new owner of this B&B. Secondary redundant probe LWCO placement is always a challenge for boiler this age........any ideas???? Thanks

Comments

  • gennady
    gennady Member Posts: 837
    edited September 2017
    One of the jobs in progress currently. This is how we do 2 LWCO. Usually on residential boilers there are no provisions for secondary LWCO, and one of them must be float type anyway.


    JUGHNEIronman
  • Steamhead
    Steamhead Member Posts: 15,343
    I hate float-type LWCOs- people don't blow them down, and their boilers dry-fire. Just had that happen on a W-M 4-80 that was only a few years old, that someone else had installed. It had the required two LWCOs, both float-type. We had suggested he have us change them to probe-type, but that was "too expensive". Yeah, right.

    Does your AHJ require float-type? If so, it would be worth lobbying them to have that changed.

    In residential sizes, the only boiler I know of that can take two probe-type LWCOs (without additional piping) is the W-M SGO series. You need to use a remote sensor for the secondary LWCO and install it in the lower try-cock tapping next to the sight glass. For gas, you can use a Carlin EZ-Gas or 201Gas in these boilers.

    We have at least one SGO installed this way but I can't find the pics quickly- I'll post them if I do.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
    JUGHNE
  • JUGHNE
    JUGHNE Member Posts: 9,765
    Not changing the boiler, just trying to save it. The house is a landmark in our town.
    I wanted info on age to justify to owner to just change existing LWCO rather than cleaning.
    No AHJ for this, even though it is a small B&B.

    It is a great old house. They did not call me, but I was aware of the lack of maint on boiler and approached the new owner who was unaware of the situation.
  • Steamhead
    Steamhead Member Posts: 15,343
    JUGHNE said:

    Some questions, this is a NG HB Smith boiler GHB2-9-2, 245,000BTUH input/196,000 output.
    Serial number is B82S ? Seems too short for SN. But would the year be 1982?

    Secondary redundant probe LWCO placement is always a challenge for boiler this age........any ideas???? Thanks

    Is there a try-cock tapping next to the sight glass?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • JUGHNE
    JUGHNE Member Posts: 9,765
    I don't see the try cock ports. (I have used them on other boiler Probe LWCO install).
    Looks to be skim port plug that never has been out...since 1982?
    I need to do another visit. Thanks
  • JUGHNE
    JUGHNE Member Posts: 9,765
    This boiler has a "drum" header. Horizontal about 24" long 8" OD.
    1-2" steam inlet in one bottom hub and 1-2" equalizer outlet out the other bottom hub. One 2" riser out of drum top hub (directly above boiler steam supply) with 2" tee above that, most edr main connected with 2" on run of tee. Lesser edr main connected to branch of that tee.

    This is 2 pipe counterflow with no drip on mains at boiler.
    Some building changes have introduced some longish 12' long 3/4" run out to rads.
    Of course the Pressuretrol is set at about 7 PSI, iron pigtail probably plugged.
    One lonely #75 air vent on return at boiler.
    TVR on most CI rads. Traps on each.

    Boiler was moved years ago into a closet, too close for good pictures.

    This runs and heats fairly well. Burners and sections need cleaning.
    Is it possible to make it worse with what I believe are upgrades?
    (New LWCO and PRV for safety concerns)
    But lowering pressure as low as possible
    Adding more venting on return and on a 1 1/4" runout that needs new pipe section.

    Any land mines with the drum header/CF piping??
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,010
    In my area (2) lwco required can be float or probe. 1 must be manual reset. They must be in separate boiler tappings.

    There's no substitute for maintinence with any LWCO.

    McDonnell Miller calls for annual maintenance and control replacement after 10 years

  • JUGHNE
    JUGHNE Member Posts: 9,765
    So using the lower sight glass/LWCO tap for a teed in second probe CO would not be correct.....same boiler tap?
    However in absence of any AHJ that location would be workable and better than no redundancy IMO.

    I may be lucky to just replace the original 1982 MM 47-2 LWCO.