I have a 2005 Grandee that isnt used that often. Recently it is making a pulsing sound and the red light on control panel stays lit and never shows 'ready' light. The tub is warm and heating...little bubbles constantly coming up from bottom. The pulsing sound seems to be coming from the circulation pump (SilentFlo 5000) which seems to be quite warm. Its hard to tell definitively, but that seems to be the problem. I have heard that they get stuck or at least the impeller does. What can anyone tell me about these? Is the pulsing sound representative of a mal-performing circulation pump? Need some help before dropping $150 on an entirely new pump and wet assembly.

Thanks
Eric

Sounds like a circ pump heading south. If you can get one for $150 you are doing better than I did when I replaced mine last year. Those little things are quite expensive.

I agree with Denny. It can make noise like that for a long time and still push water. Try removing the filter with the gray cap to see if that makes a difference. If not you can let it go until it dies. The new circ pump part number is 74427, it is smaller than the old one and I believe is self priming.

They work on a magnetic field and low or high pH can compromise the magnetic field causing it to make noise.

You could also take it apart and see if the is any obstruction in the impeller.