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Cold 3RD Floor Radiator

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  • Cold 3RD Floor Radiator

    Hi Guys
    Well I do believe I have exhausted my plumbing skills. I have a 2 story building with hot water heat that had piping in the attic about 30' up from the boiler.
    The pipes feed and return came threw the floor where two radiators were at some point in time with a wall between them. These lines have been caped off since I've owned this building.
    Last winter I remoldeled this area and removed the wall. I installed a radiator between one set of pipes and this radiator kicks. By the way this zone of piping also feeds the second floor bathroom radiator.
    Since this new bedroom was rather large and the radiator was on one side of the room I taped in to the other two pipes under the floor and installed another radiator on the other side of the room.
    To do this I had to run a 30' feed and 30' return line around the perimeter of the room with an 18" rise and 18" fall a vertical loop you could say. I installed bleeder elbows at the top of each loop on both lines.
    When I first filled the zone and bleed the lines I got good heat from the first radiator at the top of the rise and about 10 deg less from the one 30' away. Then the next time you check it a day later it's stone cold.
    You can bleed the radiator and the bleeders at the elbows until your blue in the face and no heat. While the radiator at the top of the rise kicks. Also it doesn't seem to have the pressure the other one has coming out the bleeder.
    I'm begining to think I should of hooked them in series.
    and that the hot water is going to the first radiator taking the path of least resistence and returning to the boiler and not flowing to the second.
    The pressure in the fill line is factory set with a new fill valve the guage reads 15 psi cold and I believe I've seen it 20 psi hot (not sure)
    Since it's to late to change any piping can a pump be put on the feed line in the basment to help out the BG 110 pump on the return side of the boiler. Or should I get a kerosene heater. Thanks Jake

  • #2
    Re: Cold 3RD Floor Radiator

    I'm begining to think I should of hooked them in series.
    Yup, I think that is your problem too. The water is taking the path of least resistance, that extra 18" rise (~.65PSI) is enough to divert most flow to the 'lower' radiator.

    Not possible to change any piping? Do you have any balancing valves or other flow control in the line, doesn't sound like you do or you most likely would have tried it.
    "It's a table saw, do you know where your fingers are?" Bob D. 2006


    1/20/2017 - The Beginning of a new Error


    • #3
      Re: Cold 3RD Floor Radiator

      Thanks for the reply.
      There is a typical radiator flow valve mounted on each radiator. Maybe if I just about shut the good (lower) radiator down some water would flow to the other.

      Do you think more pressure in the line or some kind of pump on the feed or return for this leg in the basement would help.

      When I first plumbed this up I had problems when I first tested it before the room was completed. I asked a local HVAC plumber about hooking the radiators in series. He told me the second radiator in line would run colder and I just had air traped in the lines of one of the vertical loops and needed to put bleeder elbows and bleeders at the top of each 18" rise. Guess I asked the wrong guy
      The only access I have to any piping without cutting up the carpeted floor or plastered walls is in the basement.


      • #4
        Re: Cold 3RD Floor Radiator

        How old is the pump? What brand and model #? If it is a B&G series 100 or larger have you looked at the impeller to see if it is in good shape? Have you thought about using monoflow tees?

        Keep in mind if you bleed out the air and get hot water, but the rad cools off and still doesn't heat, it is not an air problem.


        • #5
          Re: Cold 3RD Floor Radiator

          I am by no means a hydronic heating expert, but we have 5-3 story dormitories that are heated this way. We recently had the exact problem you have. As I understand our system we have a main supply trunk that each radiator feeds off of and returns to a common return line. We kept bleeding the lines till we had enough air to fill the whole building :-). We finally figured out we needed to change the Auto-vents (very simple, fairly inexpensive) that vent air automatically when necessary. These vents are located in the ceiling of the 3rd floor (highest part of the system) which is where the supply lines route through; they go up to the ceiling then go down to the registers below the windows. If I walked into your situation that is the first thing I would look for; may not be the answer, but it seems to have solved our problem.
          God Bless You Super Good!!!