My pump (2.5HP Hayward) has a problem - when it kicks on for the first time each day,
it makes a horribly loud buzzing noise, which goes on for about 5 seconds,
then it shuts itself off (the water does not flow while it is buzzing). Maybe
30 seconds later, it tries again, buzzes loudly, then shuts itself off again.
The pump basket is still full of water when this happens (as it's supposed to be).
If I open the pump basket and let some air in, then close it again and
start the pump, it will start up and re-prime, and work fine (though it does make
the loud buzzing sound for a second when it starts). But then the
next day, it does the same thing. You'd think it'd have an easier time when
the pump is primed, but the opposite seems to be the case.

(The pump is <1 year old.)

Any ideas?

Thanks.