Sta-Rite SR400NA "gravely" noise and fault

[DaveN007]

Hi folks, My heater goes through the normal startup process to the point where it starts blowing hot air. Then it makes sounds like gravel is bouncing around inside and it shuts down and throws the "Service Heater" light. I'm not an expert, but does this sound like a problem with the valve system that opens and lets water flow through the heater? Thanks for all attempts to "give a haircut over the phone". All thoughts are appreciated. Video of startup and sound: https://youtu.be/-6MIm9jbQy0

 

[pooldv]

Welcome to TFP!

Generally, gravelly noise in plumbing indicates cavitation, which is insufficient water flow, which supports your theory that the valves to the heater are not set correctly an restrictions flow.

 

[DaveN007]

Thanks, pooldv. Any thoughts about the video? You can skip to 1:49 to hear the noise.

 

[JamesW]

Video not showing up.

I suspect that the noise is due to low water flow. The water is probably boiling.

 

[ps0303]

If water flow is good, then you could have a broken bypass in the unit and or bad thermal regulator.