I just installed a new Silentflo 5000 exact replacement in my 19 year old Hot Springs Sovereign (still looks great!), the old circ pump finally shot craps. I've only ran it about a month since the change, and now the pump at times makes a whining / slight grinding noise like the impeller is hitting something. If I rap on it with a screwdriver handle, it will make a thumping noise for a second and then stop the impeller noise, only for it to return maybe 30 seconds later. Any ideas out there what is going on? Thanks.

Some Silent-Flo 5000 pumps develop clearance problems with the magnetic driven impellar. If you have the receipt then you should be able to get a new one. I would try to get the new E5 circ pump which replaces it.

circ. pump comes with a year part warranty fron Watkins. Get a new one.