Why is Sump pump backup running nonstop

[BWWgarage]

Happy new years.

1yr old Wayne wss330v combo sump pump with control unit / battery backup.
Water was leaking/spraying from flexible joint
I reattached flexible joint.
The back up pump keeps running.
I disconnected the backup float input to the control unit. (I tested backup float and it works correctly)
There’s no float connected to the control unit
Backup pump continues to run
Main pump does not run but will if I lift the float it works correctly (and no blockage on discharge piping)

I’m guessing:
1. Bad control unit - sending power to backup pump with no float inout
2. Bad backup pump - but shouldn’t be getting power so it has to be #1?

We did lose power yesterday so possible a power surge damaged the control unit.

Any other possibilities I’m missing?

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[tarmy]

Does that unit require a functioning float switch? It may default (since you removed the float switch) to running without the presence of one. Are you sure your test really worked. My float switch has an internal switch that can stick…so…

 

[BWWgarage]

Does that unit require a functioning float switch? It may default (since you removed the float switch) to running without the presence of one. Are you sure your test really worked. My float switch has an internal switch that can stick…so…

Thanks for thoughts:
Good point on default to run. My hunch is it doesn’t though since the float is simply an open/close. I tested with multimeter and continuity test worked as it should

The more I think about it, I get more convinced it’s the control unit and it was damaged when power went on/off.

 

[willf650]

For it to be a supervised switch the switch should read a set resistance when “open” and shorted when closed.

Theoretically it could be reverse acting and you could test that by putting a jumper in its place and see if it turn off. This wouldn’t make sense since the switch tests the opposite way when the poster says it tested correctly.

I would be doubtful either of these are the case and my vote would be for a bad control unit as well.

 

[AC-WC]

How about a check valve in the pump hose to keep the water from flushing back into the pump?

 

[BWWgarage]

Pump is a combo and I believe a single check valve (as part of system). Main pump is clearing fine. I may look deeper on this tho.

How about a check valve in the pump hose to keep the water from flushing back into the pump