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    Low heat from hydronic baseboard radiators (47 Posts)

  • izthebye izthebye @ 9:36 PM
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    Low heat from hydronic baseboard radiators

    Hope I am in the right forum!  Around 2000 I installed a radiant hot water heating system in our small 2 storey house ( 1300 sq. ft. no basement). Furnace is on the ground floor and feeds a 1-1/4" copper loop that goes around the ceiling of the ground floor. I have 6 zones. Each zone is fed through mono-flow tees (sp?) and 3/4" copper pipe to a baseboard radiator. On the ground floor, several radiators are fed from 1 zone. The return of each radiator goes through a mono-flow tee back into the 1-1/4" loop.
    The system does work, but when the outside temperature goes below freezing, it seems that very little heat comes out of many of the radiators. The second floor radiators seem to work the best, but we seldom have heat on in the bedrooms.
    I am beginning to suspect poor system design (my fault!) and the mono-flow tees/loop may have been a poor choice. I would appreciate any comments on this!
    Merry Christmas to everyone!
  • Mono-flow

    System design is crucial on a Mono-flow loop. Your ceiling loop has no problem with the upstairs convectors, but the hot water is buoyant and doesn't want to feed the lower floor convectors.
    Often wrong, never in doubt.
  • izthebye izthebye @ 3:45 PM
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    Reply

    Thanks Allan. I sort of figured it would be something like that. I'm wondering if a different circulator would help. My present circulator is an old Armstrong 125, I think. Is it possible to perhaps install a pump with a higher flow rate or several small booster pumps right at the downstairs heater valves? Are small circulator pumps with 3/4" fittings available? I don't know a whole lot about hydronic heating and flows, but I do know plumbing and electrical.
    On my lower floor radiator feeds, I can feel hot at the intake lines, but the outlet lines are barely warm. Any suggestions would be appreciated!
    Thanks,
    Hugh
  • N/A @ 4:40 PM

    how many??

    How many mono flo tee do u have for each lower raditor??
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  • izthebye izthebye @ 8:23 PM
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    reply

    2 for each. One on the incoming line and one at the outgoing line.
    Thanks
    This post was edited by an admin on December 27, 2013 8:26 PM.
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  • N/A @ 9:17 PM

    how long are

    How long the raditor and how far apart the monoflo tees related to the radiator??
  • izthebye izthebye @ 4:09 PM
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    Distances

    There are 2 x 48" of radiator in one zone. There is about a 6 foot run down to the baseboard intake.
    Another radiator (in the same zone) has a single 48" heater and about 6 feet coming down from the T.
    I am wondering if I should try larger circulating pump?
    Thanks for this.
  • N/A @ 3:26 PM

    i was asking

    How far apart are the monoflo tees going to the radiator???
  • izthebye izthebye @ 12:13 PM
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    ??

    I don't understand your question. Are you asking distance between input and output tees? It varies between 4 ft and 8 ft depending on which radiator we look at.
  • N/A @ 3:27 PM

    i was asking

    How far apart are the monoflo tees going to the radiator???
  • N/A @ 3:27 PM

    i was asking

    How far apart are the monoflo tees going to the radiator???
  • N/A @ 3:27 PM

    i was asking

    How far apart are the monoflo tees going to the radiator???
  • N/A @ 3:27 PM

    i was asking

    How far apart are the monoflo tees going to the radiator???
  • Dan Holohan Dan Holohan @ 6:14 AM
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    Ray,

    please hit Enter just once and be patient. Thanks.
    Site Administrator
    dan@heatinghelp.com













    Hug your kids.
  • Circulator

    I don't think a larger circulator will work.  You will end up with a higher electricity bill, more noise from the water going at highway speeds and convectors that won't heat.  Adding circulators on the branch piping will work, but where will you install them.  You will have to open up the walls and install access panels for each pump and then run power to each pump, no?

    So, you installed this system 13 years ago and it hasn't worked since or is this something new?
    Often wrong, never in doubt.
  • Paul48 Paul48 @ 9:36 AM
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    Hmmm

    You're getting heat to the baseboard? You said the supply pipe is hot.Are the tees installed correctly? They should not be installed in the same direction.
  • izthebye izthebye @ 5:36 PM
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    Tee directions

    Tees were definitely installed correctly!
    Thanks for asking.
  • izthebye izthebye @ 12:28 PM
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    Reply to Alan Forbes

    I don't think a larger circulator will work.  You will end up with a higher electricity bill, more noise from the water going at highway speeds and convectors that won't heat.  Higher power bills are the least of my worries! Noise is not a problem. No heat from convectors is, however.
    Adding circulators on the branch piping will work, but where will you install them.  You will have to open up the walls and install access panels for each pump and then run power to each pump, no? Nothing is in the walls. Everything is installed in a false ceiling with removable panels. Limited space but I can get at everything. Wiring is not a problem, either. Can you give me a brand name on smaller circulating pump that I can put in 3/4" pipe? This sounds like it may be a good solution. I will probably need only 2 or 3 of them. At this point expenses are not an issue either!

    So, you installed this system 13 years ago and it hasn't worked since or is this something new? Never did work right, but we don't participate in global warming. It's just gotten colder!
    Thank you all for your suggestions and comments. They are much appreciated as I live in an area where there are no real experts.....none that I have found, anyway!
    Hugh
  • Weezbo Weezbo @ 9:55 PM
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    do you have a picture ,

    of the baseboard zone that does not quite work right and it's take offs ?
    i like monoflow .
    it is one of my favorites ...
    i just haven't been able to picture clearly what is you have to deal with.

    Weezbo .
  • izthebye izthebye @ 9:11 AM
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    Picture

    Hello Weezbo and thank you for your interest in my problem.
    It will take me a couple of days to get a picture as I have to remove a number of ceiling tiles to get at it. The only radiators I have problems with are the ones that are BELOW the loop. Upstairs radiators do work. Another poster has pointed out that hot water does not like to flow downwards!
    Thanks again!
    Hugh
  • Gordy Gordy @ 9:20 AM
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    Hot water flow

    In a hydronic system hot water flows where ever you want it to up, down , sideways, forward, and backwards.

    You just have to tell it how to get there through the use of proper piping, and various valves,.....or not to. Water is stupid, and lazy will take the easiest path unless it's told different.
    This post was edited by an admin on January 2, 2014 9:24 AM.
  • izthebye izthebye @ 9:32 AM
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    Water flow

    For me, it does not want to flow down! I am looking at trying a small booster pump in the zone(s) that is giving me problems. I can feel hot water at the intake pipe of the baseboard but the outlet only gets warm. It is my easiest fix right now as we are in the middle of cold snap (-15 deg C) and I do not want to drain the system.
    thanks for you interest. 
  • Weezbo Weezbo @ 10:15 AM
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    interesting ,...

    evidently no one ever told that to the couple hundred feet on one system and the 60 feet on another i spun in last year ... hmmm...
    maybe they behave differently in warmer climates lol...
    well, see what you can do .. and i am also interested in any in line ball valves ,gates , purges unions that you might see ...or take offs from the drops and risers ..
    also if you have any actuators that have cap tubes run to a dial on the walls or any hidden within the baseboard enclosures ..K ?

    Thank you ..
    *~//: )


    By the way ,.... fluids do not like to flow thru blocked pipes , i Know that sounds demonic and like i am probably making that up, buh it is true .
    This post was edited by an admin on January 2, 2014 10:20 AM.
  • Paul48 Paul48 @ 11:19 AM
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    Don't Understand This

    " I have 6 zones. Each zone is fed through mono-flow tees (sp?) and 3/4" copper pipe to a baseboard radiator. On the ground floor, several radiators are fed from 1 zone. The return of each radiator goes through a mono-flow tee back into the 1-1/4" loop"
    You used a single mono-flow tee on the supply at the main, then split the supply to each radiator?.
  • Gordy Gordy @ 12:07 PM
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    Not demonic

    There was a problem post here a while back with same issue.....guess what restricted piping to the baseboard.

    Could be in this case. If the booster pump idea fails guess what.
  • N/A @ 10:34 AM

    dan

    As I said before, ur site takes me 4 to 5 times to get pass the bs 'test' and yes I only hit it once, its the site doing it..
  • N/A @ 10:35 AM

    just the last post

    Took me three times
  • Paul48 Paul48 @ 11:09 AM
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    Once

    Three times
  • Dan Holohan Dan Holohan @ 11:55 AM
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    One time

    One time
    Site Administrator
    dan@heatinghelp.com













    Hug your kids.
  • Dan Holohan Dan Holohan @ 11:56 AM
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    One time

    Again
    Site Administrator
    dan@heatinghelp.com













    Hug your kids.
  • Paul48 Paul48 @ 11:57 AM
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    There you go again

    with the addition...LOL
  • Dan Holohan Dan Holohan @ 11:59 AM
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    And again

    Three separate posts, Ray. Each went up in less than a second without any problems. And I'm posting form an iPad right now. No problem doing the math problems.
    Site Administrator
    dan@heatinghelp.com













    Hug your kids.
  • Gordy Gordy @ 1:13 PM
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    Ray

    Your connection must be slow, and or computer in its loading. So you may think you did not hit the submit button so you hit it again, and again, and again.
  • Hugh

    Thanks for hanging in there. Those pictures will help us see what's going on.  Take as many as you can, but specifically, we need to see the tees which feed the radiators, both on the supply and the return.

    It sounds as though you have Mono-flow tees on the supply and return - that's good.  It also seems as though you have good distance between the tees which is good as well since this will encourage water to be diverted down through the radiators.

    At this point, we want to make sure the Mono-flow tees were installed properly.

    Alan
    Often wrong, never in doubt.
  • Weezbo Weezbo @ 3:22 PM
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    it may be as you say ,

    that there is a need for a larger circ that most closely matches what you need for flow .
    and i tend to be rolling with everyone on the idea that over time the old sytle Y strainers are probably iron enriched by now .
    sometimes if there is no way over baseboard for a "Book" i will drop down into a t to get a purge valve on both ends of a single line , then i can prove flow at any time and clean out a line using force .
    and just because i install a circ today that does not mean that over 13 years the impeller or volute havent changed a bit thru erosion corrosion or sediment build ups ....
    like RJB Gordy Paul and Allen it is not as easy for us to see just what may have twisted up the zone at the moment . we probably are asked to fix many things, over the years , only to discover that it could never have worked right in the first place , that the pessimism shines through ...
    i suppose that is how we get to being sorta blunt with questions at times .. we cant see anything and sometimes it is hard to piece together words ,even when it seems evident once we look at some picture , as to what you may have meant...
    older systems have circulators on them from deep into last century . clean as a whoostle some newer ones the water quality itself clusters them up in really unbelievable periods of time .. so it is like that too, we left our x ray glasses in ,...The Other shop truck , that day..
    : )

    pictures and gauges always trim countless hours off troublesome operations .
  • izthebye izthebye @ 7:35 PM
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    Pix of 1 radiator feed

    Ok. Here are some pix of what I will call Living Room #2 radiator. I lied about the distance between tees! Photo 2 is a close up of the tees. Left is hot water into the baseboard, right is output from the baseboard.
    Photo 1 has the 1-1/4" loop line on the left with the input closest to the camera. There is a bleeder valve in the return line which is visible in photo 3.
    Both the input and output lines have 3/4" ball valves. The orange plastic lines run across the living room about 12 ft and then down 6 ft. to the radiators.
    Please note that my system has been in place 14 years and it has not really changed in performance. We just found it adequate until it got really cold. My domestic water (in the boiler) comes from a drilled well and is very soft. The only corrosion I have noticed was in a couple of leaky ball valves that I changed out.
    Water comes out of the boiler hot and returns to the boiler just a little less hot in the loop.
    Let me know if you need any more info and thanks everyone for your input and suggestions.
  • You led us on : )

    Yes, those tees are way too close together.

    I'd install a 1-1/4" full-port ball valve between the tees and throttle flow down until your convector starts to heat.

    How many more do you have like this?
    Often wrong, never in doubt.
  • Weezbo Weezbo @ 8:44 PM
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    are the takeoffs for these "several" in the walls?

    "On the ground floor, >(*"several"*) < radiators are fed from 1 zone. The return of each radiator goes through a mono-flow tee back into the 1-1/4" loop. "

    they come back to the 1& 1/4" on individual returns ?

    Fed off the 1/2" zonevalve? or is that a 3/4" zone valve?

    Weezbo .

    i am still trying to "Focus Up!" here :))
  • izthebye izthebye @ 8:59 PM
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    Feeds

    "On the ground floor, >(*"several"*) < radiators are fed from 1 zone. The return of each radiator goes through a mono-flow tee back into the 1-1/4" loop. "

    they come back to the 1& 1/4" on individual returns ?
    Yes, radiators vary in length but mostly about 8 ft.

    Fed off the 1/2" zonevalve? or is that a 3/4" zone valve?
    3/4" zone valve. At least that is what the fittings are. Hole through the valve is more like 1/4"!

    Weezbo .

    i am still trying to "Focus Up!" here :))
    This post was edited by an admin on January 2, 2014 9:00 PM.
  • izthebye izthebye @ 8:51 PM
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    I led you on.....

    Ok. How will a "throttling" ball valve in the loop affect the rest of the branches and zones? I'm kind of reluctant to break the loop at this time of the year, so I would have to put it on hold until the weather warms up.
    There is another baseboard output about 2 ft down from this one (same spacing). Would it help if I swap it to the output of the downstream one? This will give me about 30 inches between tees. The other baseboard is an upstairs bedroom that is seldom, if ever used.
    I have about 3 ft between tees on my #1 living room baseboard. That one does not perform very well. My kitchen baseboard (same zone as the living room) has about 5 ft between tees and it is worst performer of all, with the baseboard getting just slightly warm.
    I have 3/4" ball valves on all the input and output 3/4" lines. Would throttling them (at the outputs) help?
    Thanks for all this.
  • Paul48 Paul48 @ 10:01 PM
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    Zones

    You can't zone like that with mono-flow. You would have to have a 3-way valve with bypass. It is the same way when you hear someone removing a radiator from a monoflow system, and just caps the stubs. I'm surprised the system works at all.
  • Gordy Gordy @ 7:33 AM
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    Closely spaced t's

    Essentially what you have is a hydraulically decoupled baseboard because of the closely spaced t's. Much the same scenario as primary secondary piping.
  • Paul48 Paul48 @ 9:43 AM
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    Gordy

    They're monoflow tees.
  • Gordy Gordy @ 3:01 PM
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  • Paul48 Paul48 @ 9:34 PM
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    P/S

    I just can't stretch to compare it to P/S, in which one does not affect the other.That's not possible with monoflow tees. The zone valve will screw the works up anyway.B&G's designs show a single emitter, off one or two monoflow tees.Zoning is accomplished with multiple circulated mains.
  • unclejohn unclejohn @ 5:41 PM
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    Looks

    To me like the arrows are pointing toward each other which may be correct if you w2ant to force water down but the piped appear to be pointingup. Also the distancee between the tee's should be the same as the lenth of baseboard. 48" of BB 48" between tees.
  • izthebye izthebye @ 6:16 PM
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    Update and clarification

    Just to clarify, the pix are of pipes in the ceiling.
    Update: I have installed a small Watts domestic hot water circulating pump  in  the larger branch of the downstairs radiators and although it has not cured the entire problem, that radiator bank gets warmer than it ever has and the living room is habitable again. This will probably hold me over for the winter and come summer, I'll probably scrap the loop and set up a manifold and use Pex piping. The copper in the loop has probably increased in scrap value enough to pay for the Pex!
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