Polaris 3900 low RPM

[Kelly Gordon]

I have a trusty Polaris 3900 that is being finicky this season. I can't get the wheel RPM above 20, no matter what. The backup value is also firing strong and consistently, but it doesn't seem to have enough pressure to actually pull the vacuum out of corners and the like. It only manages to move the vacuum about 30% of the time.

Things I've already tried:

• Backwashed, cleaned the filters.
• Locked down the pressure value on the vacuum hose so it's completely tight (although there is still some water coming out of it)
• Checked for leaks in the hoses - nothing (although I did find a small tear at the very end of the tail)

Is it time for a rebuild kit?

One other note: My vacuum wheels are also turning to mush. They are soft and sticky and starting to leave residue on the pool liner, so those will definitely get replaced along with anything else.

 

[sktn77a]

The backup value is also firing strong and consistently, but it doesn't seem to have enough pressure to actually pull the vacuum out of corners and the like.

Then it's probably not the 3900, so a rebuild probably won't correct the issue. Sounds like you're not getting enough flow/pressure to either the backup valve or the 3900.

 

[Kelly Gordon]

Then it's probably not the 3900, so a rebuild probably won't correct the issue. Sounds like you're not getting enough flow/pressure to either the backup valve or the 3900.

Hmmmm. I actually have a LOT of water coming out of the pressure relief valve on the wall connector, even though that valve is tightened all the way. The water is bubbling at the surface with all the extra water. So I think the pressure coming from the booster pump is good. But it's not getting to the vacuum itself.

I just replaced the wall connector and pressure valve last August. Could it be bad? I made a few modifications to the vacuum itself today - tightening the solo wheel, checking the o-ring in the water system. I also put on new tires. But the RPM is still about 22.

 

[reggiehammond]

Hmmmm. I actually have a LOT of water coming out of the pressure relief valve on the wall connector, even though that valve is tightened all the way. The water is bubbling at the surface with all the extra water. So I think the pressure coming from the booster pump is good. But it's not getting to the vacuum itself.

I just replaced the wall connector and pressure valve last August. Could it be bad? I made a few modifications to the vacuum itself today - tightening the solo wheel, checking the o-ring in the water system. I also put on new wheels. But the RPM

I really sympathize as my old Polaris did a similar thing to me.
Rebuilt it, replaced parts, new lots of stuff and just couldn’t get it working well.

Finally bought a robot and pitched the Polaris in the garbage. It was a really satisfying moment…