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Hot water not moving

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shoe49
shoe49 Member Posts: 6
in Radiant Heating
With no previous experience I have built an open radiant floor system using ideas from all over the internet. My plan was to use a gas water heater to supply supplemental heat to a 400 sq ft room as well as a washing machine and an adjacent bathroom. The supply water pressure runs between 45 and 55 psi which keeps the system at the same pressures.   It is now installed and supposedly ready for service. The construction has been fun and I have learned much, or so I thought. Problem is when I switch on the power to the thermostat the pump runs but the hot water will not move through the system. I have put gallons and gallons of water through the Pex tubing in the floor as well as the copper piping to remove the air. Most of what I have read in the forums say air in the system is the problem 95% of the time. I can close off the bath and washing machine but still nothing. I installed a mixing valve with the mix going to the bath and washer instead of the floor. I'll attach photos of the system.  Do you see any glaring problems.   Any suggestions will be appreciated.  ThanksShoe49

Comments

  • icesailor
    icesailor Member Posts: 7,265
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    Doesn't work:

    Nice piping job.

    It doesn't work.

    My head is aching looking at all the faults.

    If it is an install in Massachusetts, it is totally illegal and the thought of a AHJ inspector loosing their mind at ME for doing that makes the back of my neck burn.

    But if you don't get sick from contaminated water in the system, god bless you.

    I just did Session 5 of my Massachusetts License Continuing Ed last Saturday, 10/27/12. This type of installation was covered.

    A lot of installations you reads about on the Internet may not work as advertised. Sometimes, when you mix the good with the bad, you get nothing.

    I hope that your immune system is good enough to protect you from legionella.
  • shoe49
    shoe49 Member Posts: 6
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    Hot water not moving

    I knew I was subjecting myself to ridicule when I posted but I am looking for advice on how to correct the problems.  The water will not be used for consumption, just washing clothes and showering.  Still it looks like the water should move through the piping.  Why not?
  • Gordan
    Gordan Member Posts: 891
    edited November 2012
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    Drawing arrows on a picture

    doesn't make water move in that direction. Pressure differential does. There's no way for that circulator, for instance, to make the water circulate as the arrows would have it, through that mixing valve. There are many resources on the internet on doing this correctly, and the layout is far simpler than what you have here.



    EDIT: I see now that you're not circulating through the mixing valve; that's for distribution to points of use. There's still plenty wrong with this type of system in general, and the way you have it installed in particular, that the question should be is it worth trying to fix or should you reevaluate the concept. An addition of a heat exchanger between the domestic and the radiant would be the first step. Taco makes the XPB which is a self-contained unit with outdoor reset and domestic and radiant-side circulators but it ain't cheap. It would be cheaper probably to just install a different heat source for the two functions.



    Atomization of the hot water into little droplets in a shower is the ideal way for Legionella to enter your organism, through your lungs. Consuming Legionella-laden water is not likely to cause Legionnaire's Disease, but breathing it in is.
  • Gordy
    Gordy Member Posts: 9,546
    edited November 2012
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    Manifold

    Are the flow rate adjustments on the return manifold open?



    Please heed warnings above, and isolate the potable from the radiant with an heat exchanger. Legionella is no joke, and people probably get it more than is realized in the medical community. Even healthy people can get a touch of it .



    Gordy
  • kcopp
    kcopp Member Posts: 4,432
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    My suggestion....

    is to bring in a consultant who has done radiant in your area. He can show you a good layout, look at your tube lengths in the floor and work directly w/ you...
  • shoe49
    shoe49 Member Posts: 6
    edited November 2012
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    Hot water not moving

    All return valves are open.  I disconnected the domestic piping ...no more for the shower or the washing machine.  Not to worry about Legionella!  I capped off the pipes from the mixing valve, purged all four lines as well as the copper, lowered the line pressure to 20 psi and tried the circulating pump again.  No water movement. 

    With no restrictions in the system shouldn't the water move? If not then why not?  It would seem to me that the system is nothing more than a circle with a pump and common sense says it should move.  What am I missing?

    Thanks to those of you who have offered constructive advice.

    If I hire a consultant then I will have failed in this DIY project.  The radiant system is not absolutely necessary to heat the room.  It is supplemental heat and building the system is a challenge I enjoy.
  • kcopp
    kcopp Member Posts: 4,432
    edited November 2012
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    you need to....

    keep it simple. You have way too many check valves. Move the circulator so you pull out of the mixing valve and away from the extrol.... move your circulator so it is horizontal not up on its back.... How long are the loops? I need to draw you a picture..... Were are you located? PM me...
  • shoe49
    shoe49 Member Posts: 6
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    Hot water not moving

    ps  There are four loops all about 175 feet long,
  • Paul48
    Paul48 Member Posts: 4,469
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    Questions

    What size pex? What size circulator?
  • shoe49
    shoe49 Member Posts: 6
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    Hot water not moving

    1/2 inch pex and Taco 005 SF2 1/35 hp pump
  • Paul48
    Paul48 Member Posts: 4,469
    edited November 2012
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    Circulator

    is too small. http://www.taco-hvac.com/uploads/FileLibrary/SelectingCirculators.pdf
  • Gordy
    Gordy Member Posts: 9,546
    edited November 2012
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    005

    Should still have some flow. 7' of head for 175' of pex. Should be getting 8 GPM with the 005. Even with all the loop to loops, checks, and mix valve the loops should be able to see .5GPM



    I agree with Kcopp that things need to be changed in the piping.....simplified.
  • kcopp
    kcopp Member Posts: 4,432
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    I dropped you....

    a diagram.
  • Paul48
    Paul48 Member Posts: 4,469
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    Head

    I didn't come up with 7' following Taco's instructions.
  • shoe49
    shoe49 Member Posts: 6
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    Hot water not moving

    Kcopp

    The diagram did not reach me.  Did you get my pm with my email address?

    shoe49
  • Gordan
    Gordan Member Posts: 891
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    Simplifying is simple

    In your photo, if you draw an imaginary line extending the pipe connected to the inlet flange on the circulator to where it meets the pipe coming from the water heater, that's where you should cut and connect. It cuts out all of the mixing valve mess and all but one check valve (you need none.) As kcopp said, make sure the circulator's motor is pointing sideways and not up or down; that will destroy it eventually.
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