Endless pools hydraulic resivoir frothing up and overflowing

[Fordiesel69]

Got a physical therapy pool (commercial) and whenever a very heavy person uses the underwater treadmill, it will overflow the pump resivoir and the fluid goes all over the floor of the mechanical room. It is a 3phase 208/230volt pump, and then the hoses go thru a dry well and then drop right down into the pool to the underwater treadmill hydraulic motor.

Because there are no leaks and not water in the oil, does anyone have any ideas?

Forget its a pool, its just a pump, flexible braided hoses, and an hydro motor under water. Just typical hydralics.

 

[oggb]

They sell anti-foaming agents but it's probably cavitation.

 

[Kira]

A schematic would help.
How much is a "very heavy person"?
Are you saying a heavy person taxes the hydraulic system enough effect the fluid?
So the hydraulic motor is undersized for the application?
Some sorta air leak in the pump's suction side?

 

[Fordiesel69]

-The problem seemed to occur when they replaced the hydro motor on the underwater treadmill. Again no leaks.
-People over 300lbs. 350 is the limit.
-Motor is proper size as it worked flawless for 3 years.

 

[wwillson]

@High Performance Lubricants How does your hydraulic fluid do in the foam tests? In use?

 

[High Performance Lubricants]

Send us a sample, We will need a quart. We will foam test the oil outside of your equipment in order to isolate a chemical vs mechanical foam issue.

If it does not foam in our lab you will have to find the mechanical reason. If it does foam we can fix it for you and return the oil pre treated based on the reservoir size you tell us you have.

This should be straightforward.

David

 

[dnewton3]

Dave -
You guys Rock!
That you would offer to help in such a situation is a testament to your good will and sincere care for your business reputation.

 

[Fordiesel69]

We will send a sample thanks for the offer.

 

[RDMgr]

I think the Endless Pools hydraulic oil is vegetable based. I think it's a rebrand of Fuchs Plantohyd 40N.

 

[dlundblad]

Is the motor okay? Would a faulty motor cause this? The motors fins (or whatever) are good?

Treadmill belt tension is good too?

 

[SubieRubyRoo]

Here’s a question nobody asked… when the motor was replaced, was the same oil as original used to refill the system, or was a substitute used?

 

[George Bynum]

I helped a customer run down a similar problem. Pump was in reservoir. When the pressure exceeded about 40 bar (600 psi), the oil foamed. It turned out to be a leak in a stressed pressure hose above oil level fitting shooting a fine spray of oil into the oil. The leak didn't occur until the pressure tendency to straighten the hose opened up a passage.

 

[Fordiesel69]

Here’s a question nobody asked… when the motor was replaced, was the same oil as original used to refill the system, or was a substitute used?

It was yes. But when we replaced a hydraliuc hose that failed they sent a different brand of fluid that was "appoved" and it did not look the same. It was way thinner too.

 

[SubieRubyRoo]

It was yes. But when we replaced a hydraliuc hose that failed they sent a different brand of fluid that was "appoved" and it did not look the same. It was way thinner too.

Mixing incompatible oils could definitely be your sole cause of foaming.

Has the condition been resolved yet?

 

[tnt_motorsports]

-The problem seemed to occur when they replaced the hydro motor on the underwater treadmill. Again no leaks.
-People over 300lbs. 350 is the limit.
-Motor is proper size as it worked flawless for 3 years.

A few thoughts...

• I would inspect the suction side of the hydraulic pump. These type of leaks don't leak, they draw air into the oil causing aeration and eventually foaming.
• The next thing I would check is the motor relief settings. If this is only under extreme load it would seem that the relief might be causing the aeration. If the oil didn't aerate before the mechanical work the repair is the issue.
• Does the oil temp get more elevated with the heavy person than the lighter person? Heat could be causing some of the issue.

Just my $0.02

 

[Foxtrot08]

Tag for interest.

I ran across flat out bad additive packages this year. But it doesn’t seem the case here.