Chuckles wrote:


One of the pumps, while not noisier than the other one when I'm
standing next to them, creates a sound all over the house (even in the
other zone). It is a low drdrdrdrdr sound like a cheap motor scooter
in the distance.

Smack it real good with a hammer and the drdrdrdrdr (isn't that the
sound a stuttering doctor makes???) sound will turn to a puttaputtaputta
sound (more like a small horsepower trolling motor).

;-]




If the pump, are these pumps by any chance "hot-swappable" (i.e.
chageable without draining the system)?

depends on whether there are shutoff valves on either side of it. It
could be air in the loop causing it to "cavitate" or is could be the
bearing assembly going bad or it could be several other reason. If it is
really noticeable and irritating, you may want to call in a good
contactor to check the system out such as giving it a good clean &
service. When they do, show them what it is doing.