Troubleshooting Your Transfer Pumps

Use these checks to narrow common transfer-pump symptoms before comparing replacement parts, pump heads, valves, pressure switches, motors, seals, or full pump listings.

Demand Style Diaphragm Pump

• Not priming: Check for air leaks or blockage along the suction line, including hose, clamps, fittings, and strainer. If those check out, inspect valves, valve o-ring placement, debris, swelling, or loss of valve resilience.
• Low pressure or automatic switch not shutting off: Slight valve swelling is a common cause. If replacing the valve does not solve it, source copy points to the pressure switch.
• Leaking: A ripped or cracked diaphragm is normally the cause of liquid leaking from the pump.
• No response to electrical power: Source copy suggests bypassing the pressure switch momentarily to isolate switch, brush, motor, or replacement needs.

Flexible Impeller Pump

• Low flow: Damaged, bowed, missing, worn, or ripped blades reduce flow. A worn cam, wearplate, or coverplate can also reduce flow.
• Not priming: The same issues that cause low flow can also prevent priming.
• Preventing impeller failure: Check that the inlet seacock is open, clean the suction strainer, and remove old impeller blades during replacement.

Centrifugal and Gear Pump Checks

• Centrifugal pump not priming: Check suction-line leaks or blockage, shaft rotation, impeller spacing, and whether the pump housing has liquid for self-priming models.
• Centrifugal low flow: Reverse rotation, air leaks, line blockage, restrictive fittings, or restrictive valves can reduce flow.
• Gear pump not priming: Check suction-line leaks or blockage. Source copy also notes that dry gears reduce priming ability.
• Gear pump wear: Sand or debris can wear contacting surfaces or lock up the pump.

Next step: Use onsite search for the exact pump model, replacement valve, switch, impeller, diaphragm, seal, motor, or pump head. Use live chat when visible listing details need another comparison.