On Sep 11, 8:35*pm, "John Keiser"
wrote:
After 30 years use, I replaced my water heater pump Grundfos model UP 15-18
with a new unit 3 years ago. *I just noticed it no longer seems to be
working: it just *hums very quietly, no vibration whatsoever. *The capacitor
measures 10 uf as rated. *I have 46 ohms resistance between the plug, zero
to ground. *Before I replace [fairly pricey], any other tests or ideas?
Thank you.

Sounds right , modern quality, old unit works 30 years, new unit works
3 years. I have old boiler pumps that never failed and a new
recirculator lasted about 3,