My pump makes a strange noise and I am having a real problem diagnosing it - I am hoping TFP folks may be up for brainstorming with me!!
As best as i can describe it, when it is (what I believe) "normal" sounding operation, the pump makes a clean, relatively high pitched sound. As clouds move over the solar panels, the motor rpm reduces as increases. This is because the pump runs directly off solar PV panels (through an MPPT controller).
A few weeks ago we noticed that the pump noise will suddenly change, very occasionally with an associated "rattle" of the sand filter line connected to the pump. When the pump changes, the motor sound goes down an octave - again, as best as I can describe (attached video of lower octave sounding pump motor noise.https://vimeo.com/135932808
When the pump changes sounds, i do not notice a change in flow or pressure. Also, we had the pump inspected and all seals were fine, and the bearings were fine - it was reported as being mechanically fine, with no debris or dog hair in the impeller. We also had, when we took the pump in for an inspection, a suction side leak - we had tried to patch it with silicone and plumbers wrap, which reduced the leak, but didn't eliminate it.
The pump expert (nb, just a pump expert, not a pool guy), mentioned that the suction side leak could be the issue, causing cavitation, or something internal that moves back and forth in the motor housing. Today we repaired completely since the suction side leak. When i fired up the pump it ran normally, with a high frequency motor hum, for a few minutes, but then the pump started to make the sound intermittently, and after a short while, continued to operate continuously with that lower octave operating pump motor sound.
Anyone with any best guesses? I'm running out of things to check, and baffled!
Thanks for taking a crack!
68,000litee, IG vinyl, LorentzPS 600 Solar Pump & 1/2 HP Tristar, Sandfilter, Aquarite T-15 SWG