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Having a Weil-Mclain EG boiler installed....old piping doesn't seem correct?

esco105esco105 Member Posts: 5
Hi guys, I'm a newbie to the forum. I have an appt with a contractor to install a new Weil Mclain EG-30 boiler installed. The boiler being replaced is the identical boiler. My concerns lie with the way the original boiler is piped. I have included pics of what I'm working with. From my research I have a counterflow system because there are no wet returns at the end of the mains. I did have some water hammering with the original system. I also do not have a Hartford loop but I've read it's not extremely important with a dry return system (counterflow). Can anyone tell me whether or not the near boiler piping is designed okay?


  • Leon82Leon82 Member Posts: 655
    From everything I've seen here, that tee should be split into 2 different mains off the header
  • the_donutthe_donut Member Posts: 374
    Pictures of main vents? Are those 2 spots the only drips for the main?
  • FredFred Member Posts: 8,418
    1. Was the connected radiator EDR calculated? Boiler needs to be sized to the connected radiation.
    2. There is no header. You need a header, at least 24" above the boiler water line to allow water droplets to fall out of the steam before it enters the mains.
    3. I don't see an equalizer on this system. You need an equalizer, at the end of the header. Configuration on the Header should be: Boiler riser, 2nd Boiler riser (if both are used), Main, 2nd main, equalizer at end of Header.
    4. Those two mains should be split off of the Bull Tee and each drop into the new Header
    5. Both Mains should have its own drip down to the floor.
    6. You and especially your installer must read and understand the Manufacturer's I&O manual. That provides the minimum piping configuration and sizing.
  • esco105esco105 Member Posts: 5
    The_donut, there are 2 cents, one at each end of each right and left main pipe. The only condensate return is the piping near the boiler, it shares the same pipe as the main steam pipes. Leon82, the riser tees off into 2 main steam pipes. One feeds the front of the house, the other feeds the rear.
  • esco105esco105 Member Posts: 5
    Thank you free, all that seems to make sense.
  • the_donutthe_donut Member Posts: 374
    What vents do you have and how long and what diameter is the run out to the end of main? How many stories and do you have any end of riser vents?
  • esco105esco105 Member Posts: 5
    The_donut, I'm sorry, i have no clue. I'm an amateur/just a homeowner. I believe the diameter if the mains are 4". It's a 2 family house but this heating system is only for the 1st floor apartment. I didn't check to see if I have end of riser vents but I don't remember seeing any. It looks to be the most basic kind of system.
  • FredFred Member Posts: 8,418
    From what I can see, they are probably 2" or maybe 2.5" mains and if this unit only feeds radiators on the first floor, there are no risers to worry about. Once the new boiler is installed, have the installer check and maybe replace the radiator vents, depending on their condition. I'm guessing you probably only have 4, maybe 5 radiators.
  • esco105esco105 Member Posts: 5
    Fred, should I still have a header pipe installed? According to the weil mclain manual I need a 2" header pipe feeding into the top.of the main supply pipes if installed on a counterflow system. The manual states the riser should also be on the same side as the controls, which my current configuration is not. I have included screenshots of the weil-mclain manual I am referring to. Thank you very very much for your help/input.
  • New England SteamWorksNew England SteamWorks Member Posts: 1,352
    If it's counter flow with two main branches, it should be piped like this for best performance:

    Certainly do not allow him to pipe the same as the current, that is wrong.

    New England SteamWorks
    Service, Installation, & Restoration of Steam Heating Systems
    Double DMilanD
  • MilanDMilanD Member Posts: 1,114
    And to stress it one more time: measure the connected radiator EDR to make sure boiler is sized to the connected load and not to the old boiler.
  • SuperJSuperJ Member Posts: 578
    edited March 2018
    MilanD said:

    And to stress it one more time: measure the connected radiator EDR to make sure boiler is sized to the connected load and not to the old boiler.

    If it means cancelling the appointment, or even eating a couple hundred bucks it's worth to ensure a properly sized boiler. You gotta live with it for years. This is a once in half a century opportunity to size it properly.

    That being said the EG-30 looks like about the smallest boiler in that line. Less than 50mbtu. EG Web.pdf
  • FredFred Member Posts: 8,418
    @esco105 , yes, follow the diagram that @New England SteamWorks provided, above. There is:
    - Both risers out of the boiler in use (ideal but that is a small boiler and minimum requirement is probably one riser)
    - A header
    - Both mains drop into the header
    - Both mains have a drip
    - Both drips drop to the floor
    - There is a Hartford loop
    - there is an equalizer
    - per my original post, pipe configuration into the header is:
    - boiler riser
    - boiler riser
    - riser to main
    - riser to main
    - equalizer at end of header, after the boiler risers and risers to mains
    - a little pitch in the header, towards the equalizer so that water can run into the equalizer
    - The diagram New England Steamworks provided uses a "drop Header (risers out of the boiler go up, then elbow back down into the Header. That makes for much drier Steam although the "minimum" requirement does not require a drop header, it is well worth the cost of a couple extra elbows.
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