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-   -   Low frequency whistle from baseboard (https://www.askmehelpdesk.com/showthread.php?t=417422)

  • Nov 19, 2009, 06:02 AM
    Bradpelletier8
    Low frequency whistle from baseboard
    I recently added radiant flooring under my kitchen. All I did was remove a hot water baseboard and added this in the same loop. It added 200 feet of pipe to zone 1. I used the vapor barrier pex tubing. Now not right away but two weeks later I had my furnace cleaned. A week after I started hearing a low frequency whistle coming from the first baseboard. I thought maybe I had air in system. I removed baseboard added bleeder elbows. I noticed baseboard was bent figuring air was getting caught I replace baseboard with one I had. The noise stopped. Two days later it has returned. Is it possible my circulator is not strong enough to push all that water? ALso my circulator ran dry for about a day when I did my floor heat. I turned on thermostat to get circulator to run to check for leaks. I closed shut off and forgot about circulator. The next day I was in the cellar and noticed it still running with no water. I am clueless now any help would be appreciated.
  • Nov 19, 2009, 11:17 AM
    hvac1000
    Is it possible my circulator is not strong enough to push all that water?

    YES

    ALso my circulator ran dry for about a day when I did my floor heat.

    Not good for the pump at all. Could have damaged the pump head/circulator.
  • Nov 19, 2009, 11:25 AM
    Bradpelletier8
    If that's the case how much bigger pump should I get for it. And would running a pump dry make that whistle noise.
  • Nov 19, 2009, 01:46 PM
    hvac1000
    I have no idea on pump size. That has to be done when the job is engineered by the contractor. I was actually shocked that 200 feet of PEX was added for a under floor radiant system without taking into consideration the loop size and the operating temperature of the existing system. Usually boilers for baseboard run at 170+degrees F and that is far to high a temperature for a in floor/under floor radiant system.

    I only mention the item below for your own knowledge. Water temperature,pipe size,number of bends or loops that are to long can all cause problems with the system.

    Just as an example and more are available.

    I've heard that older radiant heating systems made the floors too hot. True?

    Yes, this is a true statement to some degree. In the past, radiant heating systems were designed and installed in much the same way as a conventional baseboard system. High temperatures and simple controls were used to control the radiant heating system. These high temperatures were in fact too high from a comfort standpoint. The higher the water temperature in the floor, the higher the floor surface temperature will become. For all systems a maximum floor temperature of 85°F is maintained to ensure comfort and to keep damage to the wood floor to a minimum. In these older systems, the floor temperature could actually exceed this limit, causing the floor to feel uncomfortable.
    Today there are endless arrays of controls and piping methods to ensure this does not happen. Lower water temperatures are maintained to prevent over heating. Indoor/outdoor reset systems are used to help predict heating needs and to increase response times. Radiant heating technology is becoming more and more advanced everyday.
  • Nov 19, 2009, 01:54 PM
    Bradpelletier8
    But would that cause my whistle noise I am hearing. The floor gets very comfortable not uncomfortable hot. Regardless of the radiant heat I just said that to inform whomever would answer question. My question is I hear a whistle noise from the first baseboard in the loop. It starts a couple days after I bled the system. Heard no noise right away just two days later.
  • Nov 19, 2009, 01:58 PM
    hvac1000
    The reason I mentioned the engineering part was the fact that the noise you are hearing can come from various sources but the most suspect source witout being there to hear it is probably Your pump plus you are probably running too much head pressure on your system with 200 foot of pipe in a loop

    I wanted to add that you are probalby getting a harmonic type noise but since no engineering was done on your system my first shot would be the pump from the information you posted.
  • Nov 19, 2009, 02:17 PM
    Bradpelletier8
    I was leaning towards the pump. It really isn't harmonic though. But if it was the system why would it be fine one day then two days later start whistleing?
  • Nov 19, 2009, 02:18 PM
    Bradpelletier8
    Also what is the proper pressure in a two zone house system. I appreciate the help.
  • Nov 19, 2009, 03:02 PM
    hvac1000
    See page two on left

    http://www.cashacme.com/_images/pdf_...l/CBL_Spec.pdf

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