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  1. #1
    Join Date
    Aug 2003
    Posts
    29

    Monoflo Heat Problem

    I have a single loop monoflo system. All convectors working fine except one in hallway. Vented it till hot water started coming out. the monoflo tee about 20" before it is hot and that convector is working fine. The one in question again which is about 20" away, has a nice hot pipe entering the convector, the return is ice cold, well actually the first 6" or so is hot probably the heat from the main line. Any suggestions? Think the convector could be clogged? But why would I be getting water from the vent? Also the system has a 1 1/4" main line, and all the monoflo's come off the tee with 1/2" pipe, all IPS. The circulator is a B&G 100

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,120
    Because the water can come back through the return pipe just as easy as the supply pipe.
    Try bleeding it slowly.
    If that doesn't work.
    Its doubtfull its clogged.
    You'll need to call a tech out.
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  3. #3
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,013
    Is the convector level or slightly higher on the vent end?
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  4. #4
    Join Date
    Sep 2002
    Posts
    3,708
    Is the bleeder on the same side as the monoflow tee?

  5. #5
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    with a 20ft run off the tee you may need to let the water run out the bleeder for a minute or two to make sure all the air is out.

    just opening the bleeder till you see a small flo of water is ok with shorter runs but longer ones the air has farther to go

  6. #6
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,120
    Did he mean 20 inches as he typed, or 20 foot.
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  7. #7
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    Quote Originally Posted by beenthere View Post
    Did he mean 20 inches as he typed, or 20 foot.

    been your right guess i didnt read it to well

    eyes aint what they use to be
    or is it the brain

  8. #8
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,013
    Quote Originally Posted by tinknocker service tech View Post
    been your right guess i didnt read it to well

    eyes aint what they use to be
    or is it the brain
    There's a computer involved...... I think it's still PC to blame it on that.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  9. #9
    Join Date
    Jul 2004
    Location
    Massachusetts
    Posts
    6,837
    Step #1. Be sure the pitch of the convector to the bleed valve is uphill. That is, the bleed valve is at the top of the highest point in the convector. If it isn't repitch the convector so that it is, then rebleed and see what happens.

    Step #2. Inspect (if possible) the supply and return pipes from the main. Both MUST pitch uphill, all the way to the convector. If one pipe has begun to sag down at all, reposition it if possible so it's a constant pitch up to the convector.

    Step #3. Call in a service tech. Tell him you want a purge set-up installed on the offending circuit. The purge valve (drain) should be in between two ball valves so it can purge in both directions. Once he reactivates the system and purges the offending circuit in both directions, I guarantee your problem will be solved.
    If YOU want change, YOU have to first change.

    If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

  10. #10
    Join Date
    Jan 2002
    Location
    New Hampshire
    Posts
    1,285
    Have you measured the head loss of all of the monoflow tees and piping, to see if the currently installed pump is able to move enough water to heat ALL of the convectors?

    Monoflow tees are 10 FEET or more of equivlent length of pipe, they add up fast.

    I'll bet the pump isn't the original model, but I might be wrong. Not enough specific info to tell.

    Noel

  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,120
    Quote Originally Posted by Noel Murdough View Post

    I'll bet the pump isn't the original model, but I might be wrong. Not enough specific info to tell.

    Noel
    Or may be it is the original, with a steel impeller.
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  12. #12
    Join Date
    Mar 2007
    Location
    Myrtle Beach, SC
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    If the convector is above the main line, usually one mono-flow tee is enough. If the convector is Below the main line, you need 2 mono-flow tees, one for the supply end of the convector and one for the return end of the convector.

    If you have a long piping run to the convector, or if the convector is large, you will also need 2 mono-flow tees. If the convector is large, you may need larger tees and branch piping.

    The pump sounds fine, I have seen many mono-flow systems with only a B&G series 100 pump.

    Of course, that was when I lived & worked in Pennsylvania, Now I am in South Carolina, don't see much Hydronics down here.

    Good luck.
    Remember, Air Conditioning begins with AIR.

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
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    68,120
    Quote Originally Posted by Kevin O'Neill View Post
    The pump sounds fine, I have seen many mono-flow systems with only a B&G series 100 pump.

    .

    Then you know what happens to the old steel impellers.
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