On 15/01/2018 18:03, Roger Mills wrote:
On 15/01/2018 13:55, wrote:


The last pump wasn't stalled when I undid the whatsit. It didn't sound
too healthy though, speed unstable&Â* noises. Since it ran fine
afterwards there must have been muck in there.


So undoing the "whatsit" *didn't* crash it?

Grundfos's own instructions refer to running their pumps with the vent
plug removed to check rotation, so there is obviously no problem in
doing so.

SteveW