Pex noise with hot water baseboard heating

Russ_A

My current home is 15 years old, and it has a hotwater baseboard heating system powered by a gas furnace.  I have 3 heating zones, 1 on the first floor and 2 on the 2nd floor.  I assume for cost and convenience reasons, the builder chose Pex tubing for the installation. Specifically, the pipes are 1/2 inch Stadler Pextron.

I have been here for 3 years, and each time the 2nd floor zones startup, there is a lot of ticking/knocking noises within the walls and ceilings of the 1st floor.  I have done a lot of internet searches and realize that this is very likely due to the expansion of the pex tubes, and that they possibly were not installed the proper way.  I have had a heating company evaluate the system, and they considered it "normal" expansion noise although I questioned whether or not they had any experience with Pex as they did not seem very knowledgeable.  From reading on the internet, it sounds like Pex is much more commonly used for radiant heating than in a standard baseboard installation.

I am wondering if there are any solutions out there to help with this problem.  It's not the worst problem in the world as the heat works well, but at night the noise can be very annoying.  I can send additional specs if needed to help troubleshoot, although I am a layman when it comes to heating systems.  The tubes are exposed in the basement (running under the first floor) and are wrapped in some foam piping insulation where they are exposed.  There is absolutely no noise involved with the 1st floor zone.  I appreciate any advice on this topic.

Steve Whitbeck

PEX noise

I have used scraps of PEX tubing to do remodel baseboard piping more than a few times. PEX tubing has a higher rate of expansion than copper.

You have to install it with the expansion in mind. Also you have to keep it from rubbing on anything especially wood.

The only way to solve this problem would be to get the pipes away from things.

OR  you could modulate the boiler temperature to only supply the temperature of water that is needed to heat the house. This would have the heat on and the water flowing for much longer time periods - this would stop the noise because the expansion and contraction piriods would be much slower.