Hayward TriStar VS 950 Drive Overload, Pump Stalled, Or Failed To Start

What These Messages Mean

Typical messages:

• Check System drive overload
• Check System pump has stalled
• Check System pump failed to start

The drive monitors motor current and shaft rotation. If it sees:

• Very high current without expected acceleration, or
• Failure to reach or maintain speed after several attempts,

it posts one of these messages and stops.

Step-By-Step Troubleshooting

Step 1: Do not keep restarting

Owner-level:

• Once you see one of these messages, do not repeatedly try to start the pump. You can clear the message once to see if it was a fluke, but persistent errors need mechanical inspection.

Step 2: Inspect the wet end for visible issues

1. Turn off power and verify it is off.
2. Remove the pump lid and basket.
3. Look for broken parts or foreign objects visible down in the suction path.

If you see obvious debris, clear what you can, but you will likely need to open the housing.

Step 3: Check shaft rotation

As in previous guides:

1. Remove the motor fan shroud.
2. Turn the motor shaft with a hex key.

You will typically find:

• Completely seized shaft: strong indication of internal damage or jam.
• Very stiff shaft with scraping: parts rubbing or warped, often from heat.
• Smooth shaft: stall is not obvious at rest, so look deeper.

Step 4: Disassemble and inspect impeller, diffuser, and seal

Tech-level:

1. Remove the motor assembly from the pump housing.
2. Remove the diffuser to expose the impeller.
3. Inspect for:
   • Debris wrapped around the impeller.
   • Broken vanes.
   • Signs of melting or rubbing on diffuser or impeller.
4. Remove the impeller and inspect the shaft seal area for leaks or crusted scale.

Seal failure can let water into the motor end, swell materials, and cause drag.

Step 5: Inspect the motor and drive side

• Look for rust tracks, discoloration, or signs of water intrusion at the motor front bearing.
• Check motor connections to the drive for looseness or corrosion.

If the wet end is clean and the shaft still feels wrong, the motor bearings or internals are likely failing.

Step 6: Clear error and test carefully

After mechanical issues are corrected:

1. Reassemble the pump with new parts as needed.
2. Restore power and clear the error.
3. Start the pump at a moderate speed and watch current and watts in the diagnostics.

If it starts cleanly and runs with normal current draw, monitor for a while. If errors return, suspect the drive or motor windings.

Common Parts That Fix This Problem

• Impeller when broken or jammed.
• Diffuser when warped or damaged.
• Shaft seal kit when leaks have caused drag or bearing damage.
• Motor assembly when bearings or windings are compromised.
• Drive assembly if internal hardware cannot properly control current and speed even after mechanical repairs.

Model-Specific Notes

• The pump may attempt several starts before ultimately reporting pump has stalled. The event log will show a sequence of attempts and errors.
• Each failed start stresses the drive. Once you see a repeating pattern, stop and repair before trying again.

How To Prevent Stall And Overload Issues

• Keep debris out of skimmers and pump basket.
• Replace seals at the first sign of leakage.
• Avoid running the pump dry; it overheats seals and warp parts.
• Do not oversize impellers or modify the pump for flows outside its design.