Loss of Pressure After Pump Vibration Damage: Impeller Damage Likely

After your 1.5 HP Goulds pump vibrated loose a 1.5" discharge bushing—simultaneously shorting a power wire—you've repaired the plumbing and wiring but now have minimal pressure. Heads won't pop up. Running the pump 10 minutes with valves closed produced hot, aerated water.

What Happened

Running a centrifugal pump against a closed discharge (dead-heading) for 10 minutes is catastrophic. The water inside the pump casing absorbs all shaft energy as heat—essentially a "blender effect." This can:

• Warp or melt the impeller
• Damage the mechanical seal
• Distort the diffuser/volute
• Cook the motor bearings

Diagnosis

The hot water confirms severe overheating. Air in the discharge suggests the pump is no longer developing sufficient pressure to overcome system head, likely due to:

• Impeller vane damage reducing hydraulic efficiency
• Internal recirculation from casing/volute warping
• Mechanical seal failure drawing air

Immediate Actions

1. Stop running the pump dry or dead-headed. This causes irreversible damage in minutes.
2. Have a pump service technician evaluate. They can test flow/pressure curves and inspect the impeller.
3. Budget for repair or replacement. A 1.5 HP Goulds pump rebuild runs $300-500; replacement $600-900.

Prevention

Always open at least one zone valve before starting the pump. Install a pressure relief valve or flow switch that prevents pump operation without flow.