A Chairde
My friend has a GRUNDFOS STP 3.0B pump, and recently when powered up it stays on constantly.
The pump is working, as without it on , the Bath takes three times longer to fill.
No electrical or plumbing work was ongoing at time , or since.
Only way to stop noise is to turn unit off, when switched back on the noise starts immediately. Pump stays off for days on end, so switching ON / OFF does not work
Was wondering if anyone has any ideas?