By Jandy
Part # 6204-171
Manufacturer Code R0453700
Less than 1 hr
Pliers, Channe lock pliers
After looking at the Jandy Heater parts diagram I made a guess that the noise was coming from the inlet water side where the by pass valve was located.
I shut off pool pump and made sure all electricity was off at the breaker box for the pool equipment.
Next I used a large set of channel lock pliers (strap wrench would work as well) and unscrewed the end cap piece that allowed the valve and spring assembly to come out.
The spring was broken and the valve was cracked so I ordered a replacement from Inyopools. Installation was just as easy and seated back in the housing. Easy DIY repair