Sump Pump Check Valve

[Jonathan Chiera]

I just moved into a house with a sump pump (with backup battery pump). The backup battery pump line is joined into the main line at 45 degrees about 3ft from the basin. There seems to be only one check valve which is located in the main line only 1ft from the basin (before the backup line joins in). The pump seems to be going off every couple minutes, I opened up the cover of the basin and saw that after the pump shuts off the back-flow of water just pours right back into the basin. I assume this back-flow is coming back through the backup battery pump line since the main line has a check valve (which seems to work since I hear it slam closed after each cycle). My question is, if I go and buy a 'Quiet check valve' and install it upstream from the joint between the main line and backup line (i.e. 5ft from basin) will that solve both the back-flow issue and the loud slam (hammer) issue?
All of my research shows the second check valve installed in the backup pump line before it joins into the main line run, but this seems odd since there seem to be two check valves before the joint doing the job that only one check valve could do after the joint?
Thanks

 

[Reach4]

With one check valve, it seems to me that with one pump pumping could backflow water through the other pump.

 

[Sponsor]

 

[Jonathan Chiera]

With one check valve, it seems to me that with one pump pumping could backflow water through the other pump.

Thanks Reach4. I see what you mean, I just assumed the water would take the path of least resistance up through the check valve but you're probably right, with the check valve installed after the joint the water may have an easier time just back-flowing through the second pump instead of up through the plumbing. Seems like I should just install a second check valve dedicated to the secondary pump line and then replace the existing check valve in the main line with a quieter one. This would solve the back-flow issue i'm currently having as well as the noise issue of the main check valve.
Cheers

 

[Reach4]

Seems like I should just install a second check valve dedicated to the secondary pump line and then replace the existing check valve in the main line with a quieter one. This would solve the back-flow issue i'm currently having as well as the noise issue of the main check valve.

If you could move the noisy check valve to the backup pump, that could be good.