Hayward TriStar VS 950 "Communication Failed" Or Keypad Not Responding

What "Communication Failed" Means On This Pump

The pump can detect two main types of comm problems:

• Between the user interface (display/keypad) and the drive.
• Between the drive and external Hayward control via the comm bus.

If those links fail, you may see a Check System communication failed message and lose control or feedback.

Step-By-Step Troubleshooting

Step 1: Clarify which device is misbehaving

• If the front keypad display is blank or garbled, suspect the interface to the drive.
• If the keypad works locally but automation cannot control speed or see the pump, suspect the external comm bus.

Step 2: Check keypad to drive connection

For pumps with a wall-mounted interface or rotated keypad:

1. Turn off power.
2. Inspect the low-voltage cable between the keypad and drive.
3. Confirm it is routed through the proper opening and terminated on the correct connectors.
4. Check for corrosion, bent pins, or loose terminal blocks.

Make sure cable jackets are clamped in liquid-tight cord grips so water cannot wick into the drive.

Step 3: Inspect Hayward comm bus wiring

If connected to a Hayward control:

1. Confirm that the comm bus cable is landed on the correct terminals at both pump and controller.
2. Verify polarity on data lines; reversed conductors can break communication.
3. Check for splices, corrosion, or damage along the run.

Use cable rated for the environment and distance.

Step 4: Check bus addressing and configuration

On the pump:

1. In the Configuration menu, verify Remote Control Mode is set to Standalone/Hayward when using a compatible Hayward control.
2. Confirm the pump's bus address is set correctly for that control family.

On the Hayward control:

• Check that the pump is enrolled or configured as a device and that there are no address conflicts.

Step 5: Test in standalone mode

To isolate automation:

1. Temporarily set Remote Control Mode to Standalone/Hayward.
2. Use local speed buttons to command the pump.
3. If the pump works fine locally, the internal link is good and the issue is with automation wiring or configuration.

Common Parts And Fixes

• Replacement keypad or interface cable when physical damage or corrosion is found.
• New terminal blocks or cleaned/re-terminated connections on the comm bus.
• In rare cases, drive replacement if comm circuitry is damaged.

Model-Specific Notes

• Wall-mounted interfaces must use suitable multi-conductor cable and proper sealing of conduit openings to avoid water ingress.
• When in Relay Control mode, the pump ignores certain direct speed commands. That is not a comm failure; it is configuration.

How To Prevent Communication Issues

• Use proper low-voltage cable, not random leftover wire.
• Route data cables separately from high-voltage conductors where possible.
• Seal all conduit entries to keep water out of low-voltage compartments.