I'm having some trouble keeping my Hayward DV4000 vacuuming, it seems to work for a couple minutes and then just stops moving around. If I put some tension on the vacuum hose it does start to pulse again but stops if I let go. When I first got the vacuum a couple months ago it worked perfectly and would happily wander around the pool for hours at a time.
There does not appear to be a leak in the hose (I did have another hose that I could hear a pinhole leak) but I noticed that if I draw the hose and vacuum up out of the water there does appear to be air being drawn in right near the top where the white ring is located but I don't know if this is normal or not. I do not have the ability to balance the pressure between returns since I only have one suction point that I can use but the suction strength looked to be in the right range from the test adapter. Is there anything else I can check?