[RE-wrenches] Water system with Grundfos SQFlex

Bradley Bassett bbassett2 at gmail.com
Sat May 25 18:40:20 PDT 2024


I have a water system with a Grundfos SQFlex SQF3-2 pump. I'm getting water
flow in reverse either through the pump or a leak up to the pump. My
question is if the check valve on the top of the pump is not sealing, will
the progressive cavity pump allow water to flow through the pump in
reverse? I'd think that with a positive displacement pump it would not,
except very slowly or if it turned the motor backwards which I think would
be very unlikely. There is about 100 psi head on  the pump.

I think it's most likely I have a leak somewhere in the plumbing, and of
course another failed check valve farther up in the plumbing. It's possible
to get failures even with redundant protection if you have two concurrent
failures, which I must have here.

Brad Bassett
Old time solar guy who used to do solar pumping back in the '80's and
'90's. Mostly retired now.
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