Slayer.. thanks much for the input and suggestions. I’m following along with the concept you presented of pressure drop right as the water enters the pump due to the reducer.
Keeping it simple... you are suggesting the line leaving the mixing valve to the pump go from 2 1/2 to 3 immediately after leaving the valve, and only reduce to 2 1/2 at the last minute where it enters the boiler, yes..?
That keeps as much 3” in the loop as possible allowing the water to settle..
In essence.. that deals with the cavitation before the pump, so we aren’t dealing with the effects of it after the pump...?
Yeah, the problem is before the pump. You don't have enough room as it stands between the mix valve and pump to solve the problem.
Your only option is to relocate the mixer further back, and run the correct length of 3.0 dia to the pump or fab a tank. You guys will waste time and money to rig it like you're talking, and you will be back and it will damage your brand of your company. Fix it right, and be done with it. Call B&G tech, and talk to an engineer, and they will confirm my two options.
The pitting on the output will be solved once you correct the entering cavitation issue, but since you're having all of this fun, I'd put the 2.5/3.0 reducer right at the boiler intake and run 3.0 from pump to boiler.
