Polaris 3900 back up valve very weak


New member
Dec 16, 2019
Sydney, Australia
Hi guys
I have a Polaris Sport 3900. The back up valve is very weak so it will typically stay stuck in the same corner.
I have spent some time reading the forums but couldn’t find the answer.
check this link for the videos: iCloud
In the past month I have replaced the wall fitting and also back up valve.
the RPM is running at 30 ( revolutions in the water)
The videos above include
1) normal operation
2) out of the water general leaky backup valve
3) a back up valve operating then going back to normal
4) 2 examples of how weak the back up valve is. You can see the Polaris hardly moves

love to get any tips and tricks you may have. Thanks in advance!!!
Last edited:


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Welcome to TFP.

Have you tried replacing the backup valve?
Thread Status
Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.