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Loud baseboard heating pipes

We have replaced the circulating pump, the water lines have been bled in every room several times, and no air comes out. The reducing valve has also been replaced. We hear water flow through pipes in every room, but the pipes in the room furthest from circulating pump and boiler make a loud banging sound for the first 10 seconds the pump is running. When the pumps shuts off, the same loud baning sound occurs. Any suggestions?

Re: Loud baseboard heating pipes

Add more pipe straps and clamps to reduce their movement. Be carefull not to damage the pipes. See if it works.

Re: Loud baseboard heating pipes


I assume you have metal pipes (and not PEX plastic) for your heating system (copper or steel); the banging noises you describe are caused by metal expansion noise---as the hot boiler water is pumped thru the piping, the metal expands & rubs against the holes in the wood floorboards where the baseboard supply & return pipes enter & leave the heated room area.

It is also common to hear expansion noises from the baseboard elements themselves, usually because the plastic expansion pads on the holding brackets are missing.

Several conditions could cause the noise problems; try checking the boiler gauge; the hot water should not exceed 180 degrees while the boiler is firing; if it does, remove the aquastat cover & reduce the water heat limit dials to low temp: 140 degrees & hi temp to 160 degrees; also try widening (if you can) the holes where the pipe goes thru the floorboards without damaging the pipes, or try squirting some high heat caulking compound (red color, heating supply stores) into the holes.

The sound of water rushing thru the pipes indicates you still have some air in there, or the circulatiing pump is still too large for the system---could you post the model # & make of the new & old pump.

Re: Loud baseboard heating pipes

I have a similar problem with noisy pipes.. We have lived in our house for the past 16 years, and are used to the mild pinging noises of our heating system. However, one month ago, we had a new furnace installed and ever since, we hear knocking and banging noises throughout the house when the hot water is flowing thru the baseboard metal pipes. Is it possible that these new noises are not caused by the water temp, but rather by a higher flow of the hot water by the water pump of the new furnace? The installer checked for air and said that was not the problem, and that we would have to live with the problem!
Thanks in advance for any advice anyone could supply.

Re: Loud baseboard heating pipes


Please read the post of 12/10 as a guide and call back the installer of the new boiler and talk to the owner or manager of the installation company that did the install----he'll simply have to send out someone else that is more experienced with the problems of metal pipe expansion so that the problem can be resolved, or at least greatly reduced-----it's simply an unacceptable answer to say "that you'll have to live with it", when this type of problem can be fixed to the satisfaction of the homeowner.

If you attack the problem first using this approach, you probably won't have to pay anything---they can try reducing the water temp at the aquastat, or installing plastic seats on the baseboard brackets, and use other methods to try & reduce contact noise when the metal piping expands when the hot water is pumped thru the pipes.

Re: Loud baseboard heating pipes

There was an Ask TOH episode about this issue and how to cure it ;) I suggest that you watch more TV :D

Pipes move and you must allow for that movement or prevent it. Heated pipes move a lot and you can't stop that. They must move freely inside the baseboard units and should have flexible sections in long runs to allow for that. The isolation clips must be installed where needed and in good condition. Heat is to be felt, not heard- and any contractor who says otherwise needs to be put in the "time-out corner" till he understands that! :eek:


Re: Loud baseboard heating pipes
Pelton wrote:

... or installing plastic seats on the baseboard brackets

Those plastic seats seem to be quite effective in reducing the noise. I'm missing a few. Where can I buy more?

Re: Loud baseboard heating pipes

Consult the Yellow Pages under "Heating Equipment---Parts & Supplies' for heating equipment parts in your area----it's often effective to cut up some plastic gallon milk cartons with a utility knife to get the plastic pieces you need for this project; they can usually be formed with a small propane torch so they'll stay in place when seated between the aluminum fin elements & the metal holders.

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