I recently had some baseboard heat pipes replaced in my house during a renovation. The baseboard system was previously all copper pipes. In the renovation the contractor used pex pipe for the return lines in place of copper. The baseboard heat elements (with fins ) is still copper. The returns run under the heating elements.
Now when the heat comes on the pex pipes expand and pop out from the baseboard heat covers by as much as 6 -9 inches from the baseboard covers in a 10-15 foot section of the system. It is clear that the pex pipe has a much greater thermal expansion than copper pipes when heated. In an attempt to resolve this, the contractor has used some form of clips to restrain the pex pipes from popping out.
The thermal expansion is obviously still taking place and while the clips keep the pex pipes within the baseboard covers, I am concerned that the expansion and contraction will cause the pex fastening connections to loosen over time and we'll have a leak; or the plastic pipes rubbing against other parts of the baseboard when it expands and contracts with cause wear and result in a leak
Is this thermal expansion a common problem with pex pipes used in baseboard heating systems ?
Does anyone have experience with the use of pex pipes and baseboard heat ?