Originally my solar heating system did not have a VRV, so I added one, it's at the low end of the panels near where the cold water feeds in. I'm now hearing a little bit of water hammer when the solar valve comes on. Is this an issue? It's not too bad, just a few mild thumps.
Does it have something to do with this check valve where the solar returns:
I've always thought that valve was installed wrong, it's vertical when it should be horizontal, so the flapper doesn't close the way it should.