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  1. #1
    Join Date
    Jan 2012
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    1

    Unhappy Noisy hot water heating pipes.

    Acton, MA

    The house was built about 50 years ago and the 2nd story addition was put on 20 years ago.
    We use oil and the heat is produced by forced hot water system.
    Until a year ago we had the two systems working but they were getting very old.
    Since we installed a new high efficiency heating system the pipes on the 2nd floor make major clicking and hammering noises!
    The plumbers who have come and listened to the sound suspect the pipes on the second floor are expanding and hitting the floor boards. They suggest we have the floor removed (carpet) so they can fix the pipes. This is a major undertaking and we can't quite pinpoint all those areas where the noise comes from!

    Is there a different solution?

  2. #2
    Join Date
    Aug 2008
    Posts
    95

    Default Re: Noisy hot water heating pipes.

    I would get a second opinion from another contractor who is experienced in hot water heating; consult the Yellow Pages under "Heating Contractors" & check their display ad for those specializing in hydronic heat.

    I assume you're saying that they are talking about removing a considerable amount of carpeting, & not just the areas immediately around the supply/return piping as it goes into the floorboards; I'm also assuming that the present piping system is now 1/2" or 3/4" copper tubing & is combined into one, or is using zone valves or zone circulators to supply hot water to the 1st & 2nd floors???

    The first step is to get an accurate diagnosis of exactly what is happening to make the noise, and some minor remedies should be tried first, such as temporarily reducing the boiler water temp (usually 180 to 200 degrees) down to, say 160 (by simply adjusting the aquastat controls) to see if that makes a difference; since it's only on the 2nd floor, one still has to suspect the possibility of air in the piping (which would under normal circumstances, gravitate to the highest point in the system, which is the 2nd floor), and thus, bleed the 2nd floor bleed valves on the rads or baseboard to get any air out.

    Aside from air in the pipes, the biggest cause of the pipe noise you describe is the natural thermal expansion of the copper tubing as the 180 degree water flows thru the piping when the system calls for heat; if you have baseboard convectors, these must contain plastic inserts inside the unit to cushion & separate the finned elements (upon which hey sit) from the metal brackets that hold the finned elements in place; if the plastic "cushions" are missing, you will get a lot of noise as the fin-tubes expand from the hot water that flows thru and the expanding elements slide along the cushion-less metal holding brackets.

    Sometimes when a new boiler is installed the technician installs a circulator pump that is too large for the system (often it's the pump that comes with the new boiler); larger pumps with a lot of gallons per minute flow rate & "head" are not needed in a forced hot water system; modern practice is to install a low-head pump with 10' of "head" which is a pump the size of your fist, with a GPM flow rate of approx 20 GPM, such as a Taco 007---in most cases, the gentle flow obtained from such a pump is all that's needed to distribute the hot water around the system, even if it involves servicing 2 floors---if you have a larger pump on there now with a flow rate of, say 40, this is too much & could well create noise in the system as it circulates the water.

    Often the noise comes from the point where the supply/return pipes enter the floorboards, applying additional plastic-coated pipe hold-down clamps to the piping near to where the noise seems to be emanating from should be tried first; if THAT doesn't work, it should be possible to widen the holes at the floorboard pipe holes, without removing any carpeting; sometimes injecting high heat caulking compound into the pipe holes will see a noticeable improvement; often a short piece of PEX plastic tubing or neoprene hose can be attached with proper connectors to the copper line near the floorboard holes as an effective way of reducing noise.

    There are copper piping insert fittings that act as an accordion (I assume you have copper pipes?) called expansion compensators made by Metraflex, Flexicraft & others that can absorb the expansion of the copper piping & thus minimize floorboard noises; PEX plastic piping inserts & braided stainless steel couplers are also used for the same purpose; another method is to add MORE ELBOWS to the copper/metal pipe runs, if there is room (known as piping offsets), especially if under-floor access to the supply/return pipes is possible) that will also serve to absorb the thermal expansion & reduce noise.

    http://flexicraft.com/Metal_Expansion_Joints/
    http://www.metraflex.com/comp_std_hpff.php
    Last edited by brewster; 01-25-2012 at 11:30 PM.

  3. #3
    Join Date
    Feb 2012
    Posts
    92

    Default Re: Noisy hot water heating pipes.

    There is a ton of things that can cause this and I think ripping into the floor is not a good idea it sounds like your system may not have an air handler allowing for the air to be released from the pipes long as the system hasn't been bled or when new water comes into the system without a air handler its going to bang and make funny noises have someone who knows boilers and radiant heating look at it 9 times out of 10 its a air issue.

  4. #4
    Join Date
    Feb 2010
    Location
    South*East
    Posts
    1,227

    Default Re: Noisy hot water heating pipes.

    Quote Originally Posted by plumbingjim17 View Post
    There is a ton of things that can cause this and I think ripping into the floor is not a good idea it sounds like your system may not have an air handler allowing for the air to be released from the pipes long as the system hasn't been bled or when new water comes into the system without a air handler its going to bang and make funny noises have someone who knows boilers and radiant heating look at it 9 times out of 10 its a air issue.
    It sounds like your confused about hot water heating systems. In your post you have mentioned three types. In most cases air handlers are used in warm air systems. New water doesn't enter a hot water system unless the system is drained. Other then small amounts for make up, nowhere near enough to add air into the system. Air in a hot water system doesn't make banging sounds. What it will do is stop the system from circulating. Any noise created by air would sound like water running. The noise they are hearing is do to expansion and contraction. I would start checking were the heat lines come through the floor. The holes for the heating pipe should be large enough to allow the pipe to move. If your heat is from copper fin baseboard you will hear pinging sounds from the fins as the move. They do make expansion joints that can be installed in the base board to eliminate some of the noise created by the movement. It will not be totally quiet but it will help.

    John

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