[HRLand]

I don't install systems but was setting the clock today for a builder we work with. While a zone was working the whole pipe from the basement to the valve box vibrated loudly and when zones changed it was worse. Anyone have an idea of what this might be? I put a call in to the company that installs their systems but haven't heard from them yet and a buyer is having the home inspected tomorrow.

[Dale Wiley]

Water hammer... too much pressure on the system likely.

Check on the static pressure to see what it is.

It made need a pressure reduction device.

[tom]

Water hammer does sound like the problem. As Dale mentioned check the water pressure. A water hammer arrestor might be needed in addition to a pressure reducer/regulator