Hayward Aquanaut 400 - gathers bubbles, floats up

[dlp755]

Hayward Aquanaut 400 went on its maiden voyage this weekend. Similar models are the Hayward Phoenix X4, and the Hayward/Poolvergneugen 'The PoolCleaner' 4-wheel). The pool bottom was fairly silty but without leaves etc., after an initial manual vac to waste 10 days ago.)

Aquanaut 400 somehow seems to be gathering bubbles on its plastic surface & on the attached suction hose, which makes it float up from the bottom of the pool. (Even after removing the floats from the first section of suction hose.)

It only takes about 1 hour or at most 2 running for the Aquanaut 400 to accumulate air bubbles and float up, and then it 'moonwalks' rather than vacuuming.

I don't have an ozone system, and I use the standard TFP protocol, and my chemistry readings per TF Test Kit are spot-on for today's 60F water. I do have some very tiny air bubbles coming out the return jets (filter valve spider gasket likely needs replacing again), but all returns are far from the Aquanaut and pointed up toward the surface, so air is definitely not being shot up under it.


Can anyone tell me how/why this would happen?

Anyone else experience something like this? If so, what was the fix?
Lead weights?

 

[setsailsoon]

Are you meaning that bubbles accumulate inside the unit? How fast are the wheels turning? Do you have enough hose to reach both ends of the pool?

 

[dlp755]

Yes, definitely enough hose sections. (Had 8 from the center of longest wall with old Zodiac MX8 which reached everywhere, so added a 9th section on Aquanaut.)

Only running at 5.5 RPM. (Manual says 12-14 RPM, but that it will clean at 8 but won't climb walls.)
I wasn't intending it to be a wall-climber. It does come with a Small & Large debris/water intake to swap out for the Medium installed. Maybe it is not "sucking itself down enough" at 5.5 RPM?

But it's clearly denser than water and has no internal flotation, and is sucking the floor, so I can't understand why it is floating at all.

When I knock all of the bubbles off with a pole skimmer, it returns to the floor & works (for an hour or so).

 

[crusemm]

From the manual it looks like 8 rpm is the absolute minimum, therefore not enough flow to operate properly. You may be getting air trapped in your hose and since your flow is so low, you are not "sweepinf" the air out of the line and it is accumulating enough to pull the assembly out of the water.

 

[dlp755]

But it's been sweeping along off & on for 3 days (Aquanaut & suction hose getting whacked with a skimmer pole every 2 hours when running), so I would think that any air in the hose would have long ago been knocked loose from the inside of the hoses & Aquanaut (I did invert it while whacking it to make sure any internal bubbles come loose), and run up thru the pump & filter & blown out the return jets.

How is air accumulating on (or in) the Aquanaut at that point? I am baffled.

 

[crusemm]

How are the air bubbles getting on the sides of the robot? it's the same air, its just getting trapped in the hose instead of on the sides of the robot. That amount of air bubbles(in your picture) could not be whats lifting your robot. My guess based off of the diagrams and your description is that some part of the water flow is what causes it to drive along the bottom, and part of this motion through the water provides "down force" on the machine (Think spoilers on F1 cars). Too little flow-> too little down force-> robot eventually floats up, probably when some amount of air either develops in the hose or robot body or both. Increase your water flow to achieve the proper minimum RPM and your problem should be solved, and if not it's a good first step in troubleshooting.