Sun sun is rated 220vac at 50hz. So it is not the right choice in the US. Any circulating pump mounted improperly will create noise. If you look closely how these pumps are constructed it should not create such unwanted noise. The rotor is a floating magnet inside the stator with the ac
power. The only point of contact is at the tip of the shaft to align it with the body. The best way to mount it is horizontal. Mounting it at a greater angle will result on the rotor to be jumping up and down thus creating that noise.