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Noisy Pex

Kungur Member Posts: 49
I know that pex epand when it gets warm but I have a question. I nstalled a staple up with transfer plates and left the end"curve" between the joist free. It seems that the pex makes more noise now than it did in the early part of the heating season.

BTW is there any remedy to quiet it down?



  • Paul Pollets
    Paul Pollets Member Posts: 3,620

    a pex staple-up application can make noise if not controlled by a mixing valve and motor actuator. slugs of hot water expand the plates and their is often a ticking sound, which can be quite annoying.. automating the mixed temperature eliminates the problem, if the tubing runs were installed correctly, and the pex is not touching the wood framing.
  • furthur
    furthur Member Posts: 25
    quiet pex

    Kungar, that is about when I started to really notice the noise, in the spring.  My final fix was to tear out the hepex and install pex-al-pex.  I don't have outdoor reset, but the system is silent, now.  Outdoor reset and mixing might help, I dunno, but I'm pretty much sold on PAP for plated staple-up.

    Just a doit yourselfer, learning the hard way, as usual.
  • CMadatMe
    CMadatMe Member Posts: 3,086
    Get Rid of the Thermostatic Valve

    Change the thermostatic out to a Taco I-Valve w/odr. It will fit in the same spot as the existing valve and be a whole heck of a better investment then changing the tubing out. The problem is cold plates being hit by hotter water then what is needed to overcome the heat loss. Not only will it solve the noise problem but it will provide better overall comfort in the rooms.
    "The bitter taste of a poor installation remains much longer than the sweet taste of the lowest price."
  • Kungur
    Kungur Member Posts: 49
    The noise is at the end of the lools.

    The noise seems to be coming from the end of each lop between the joists. Yesterday as I was"On the Throne" I heard the thermostat click on and the noise started at one end of the bathroom and slowly moved to the other end. Only at the end of the joist bay. It only lasts for  a few moments. And it is the same in a few other places in the house.

    Thought I might take down the insulation and do a visual when the thermostat calls for heat.
  • Kungur
    Kungur Member Posts: 49
    I meant Loops!

    I meant Loops!
  • Randy Baerg
    Randy Baerg Member Posts: 26
    expansion noise reduced by reset temp.

    The more the zone cycles the more temperature variation and expansion noise you will have. If you use an outdoor reset control to effectively lower the supply temperature then the thermostat will have to call for much longer cycles.

    Two fold effect is that you have less cycling so the pipe is not expanding and contracting so often and with lower temperature there is physically less expansion of the tubing.

    Slamming a zone with full design temperature water then shutting it off all the time to control temperature will lead to the most noise. This would probably be worse during milder outdoor weather.

    In a theoretically perfect zone the supply water temperature would be so low that the thermostat / zone would stay on continuously at this low temp. So once it started up the only time you would get expansion/contraction noises would be more gradually as the outdoor temperature changed.

    Plus you get energy savings and fewer room temp swings. not a bad deal.
  • zacmobile
    zacmobile Member Posts: 211
    edited March 2011
    ticks & reset

    As stated above, If you install a 3 or 4 way mixing valve with outdoor reset your system will be silent.

    I actually just started up a 5000 sq ft. staple down oxy-barrier in between sleepers and it is completely silent, no mixing but it is a geo system with a 60 gal buffer tank witch is running on outdoor reset.
  • Kungur
    Kungur Member Posts: 49
    I have a 3 Way

    I do have a Tekmar 3 way mixing valve. I am exploring the reset idea.
  • Paul Pollets
    Paul Pollets Member Posts: 3,620
    Finish what was started

    Put the motorized actuator on the 3way and connect it to a Tekmar control and your noise will disappear.
  • Kungur
    Kungur Member Posts: 49
    I think I figured it out!

    The other night while lying in bed "the noise" started again and it got me to thinking. Why did this all of sudden start? As I was thinking back to"adjustment" I made I rememebered. Since I have a coal stoker boiler I have been playing around with adjustments and one that I did was to adjust the feed rate of coal AND play with the mixing Valve. So yesterday AM I went down and adjusted the mixing valve to blend in more return water and the problem has seemed to disappear!

    As to the suggestion about the motor and controller for outdoor reset. Tha is very much on my To Do List.
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