I recently replaced my Sta-rite DE filter with a new Hayward 210t sand filter with a multiport valve for my roughly 10k gallon in ground pool. The new filter works great...with the exception of the noise it makes . The noise seems to be coming from the multiport valve. To give you an idea of the setup, I have a 1 1/2 HP Challenger pump with a 2" output valve. All the other pipes are also 2" coming from and going to the pool. Since the multiport valve has 1 1/2" in's and out's, I had step down the size of the pipe going in and step up the size of the pipe going out.
I'm not really sure how to describe the sound...its like a constant "currrr" (I realize that doesn't really help). Any ideas on whats causing it and how to fix it? I've opened up the valve, nothing seems to be rattling around inside. I've back-washed and rinsed numerous times (I should note the noise is not present when in rinse position) with no success. Is it simply and issue of too much pressure from the pump to the valve? Would putting some sort of gate valve between the pump and the valve to slow the flow be helpful or harmful? Any ideas or suggestions would be greatly appreciated.
I also have pictures of the setup if needed. Please let me know if you need any other info to help solve this mystery.