Circulation pump sounds ugly dry testing... is that right?

[dfavelo]

Hello all, new member.  Just was given a free hot tub.  Opened it up, and I have a few things to fix.  When we dry tested the circulation pump, it does not sounds like a nice, smooth pump.  Instead, it sounds a bit clunky.  My father-in-law says that that might be because it is not supposed to dry run.  We're not sure.  A new pump is about $150, but I don't want to spend that yet without being sure.  This is a 1994 sweetwater.  The pump is a Laing SM-909-NHW.
Thank you so much for the help in advance!

[Dr. Spa™ Ret.]

Running a pump dry can burn up the seals almost instantly. They're water  cooled and water lubricated.

[clover]

The pump you are refering to has an impellar that is not driven on a motor shaft, but one that is held in suspension and driven magnetically which is probably the reason for the sound you are hearing.  Make your judgement call after filling the tub and running the pump.

[Chas]

Plus one.