Troubleshooting hydronic systems can be challenging, as the pipes are hidden behind walls. Your imagination has to help you “see” the routing of the piping. In addition, a component in one part of the system could affect the operation in another. An example of this could be if the relief valve is leaking. A faulty relief valve may cause this, or it could be caused by a flooded expansion tank or a malfunctioning pressure-reducing valve. You would hate to replace the relief valve and see if you have the same issue.

To help diagnose system problems, a checklist like the one below could point you in the right direction. I hope this helps you on your next hydronic problem call.