I have a Balboa 2000 M7 set up running three Waterway Executive 48F 4.5-hp pumps. My #1 pump is a two speed with the low speed kicking in for the heater and filter cycles. It is a few years old and getting noisy (mostly the rear motor bearing but probably more) and I have decided to replace the entire #1 wet/dry assy so I quit waking up the neighbors.
It has 2" suction and 2" discharge. I see it advertised that 2.5" suction is quieter. Would it do me any good to step up to 2.5" before the pump input and go with a 2.5" suction wet end? Or would it really not make a significant difference with the noise since the rest of the line is only 2".
Thanks!
floater

The best thing you could do is insulate the cabinet that the motor resides in. You can go as far as to purchase the Dynamat (sold at automotive electronics stores, such as Best Buy and such) which is a thin, sound deadening material. Stepping up to a larger inlet won't net much reduction in sound, since the sound they are referring to is the water movement. Since you have 2" lines already, you may actually increase the noise, by making a lower pressure area just ahead of the pump which can induce the water into forming bubbles....which is a lot noisier. I would stick with the 2" and work on preventing the sound from escaping the cabinet. You may find that just a new pump/motor is all you need.