Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Weil-mclain ultr 230 air in monflo system

Tony_23 Member Posts: 1,033
Just made what I hope to be the last trip to a job like that. Overhead Monoflo in iron w/ cast tees. How they EVER bled it before is beyond me. I ended up drilling and tapping the trunk in five places and installing auto-vents. Every time it got to 135+ supply temp it would lock up and only circulate the trunk.

Good luck !



  • jim_31
    jim_31 Member Posts: 4
    momoflo air problems

    Removed 50+ year old conversion and installed a new Weil-McLain ultra 230. Old system had 3 zones with seperate pumps on return piping using flow control valves in supply.We installed boiler per manufactures drawings, we are pumping away from the boiler with a grundfos up 26-99 pump into trhee zones with zone valves and 3 individule pumps grundfos ups 15-58. we also installed a boiler mate water heater with independent pump taco 014 per boiler specs also with zone valve to prevent migration. The problem we are having is the mono-flo heating system keeps getting air bound but only in one zone even though we have bleed system many times and that there is a sparco bleed in supply line at diaghragm tank and water fill valve.
  • Floyd
    Floyd Member Posts: 429
    With a monoflo system....

    you are going to need to have a way to bleed every monoflo loop at the highest point of each loop. No shortcut for it.. just has to be that way to get the air out. Sorry, but somethings are just that way.....

  • Mono-Flo Air

    Gees,,,,,,, I can`t understand why your having this problem.
    I`ve got Mono-Flo, 3 zones, steel mains, pri/sec, a "simple" scoop w/dia. tank, and I never have a prob. Can you get some pics of what set-up around the boiler you have there?
    JERRYG Member Posts: 11
    ultra piping

    I think if you consult the install manual you will find that the Ultra is only to be installed as primary/secondary piped.the boiler is to be in the secondary loop.The system will then be free of the boiler pressure drop.
This discussion has been closed.