Digital controller displays E04 and pump stops shortly after starting

Safety first: Turn off power before opening any part of the pump or plumbing.

• Prime the pump: Remove the pump lid and fill the pump housing completely with clean water. Reinstall the lid, ensuring the lid O-ring is clean and lubricated with silicone grease. Start the pump and observe if it maintains prime.
• Inspect suction-side fittings: Check unions, elbows, and valves on the suction side for air leaks. Look for bubbles in the pump lid while running. Tighten unions and replace worn O-rings or PTFE tape as needed.
• Clean skimmer and pump baskets: Empty the skimmer basket and the Calpeda pump strainer basket. Remove any debris lodged in the suction port.
• Check for blocked lines: If suction remains weak, backflush or blow out the suction line using a suitable line blower or garden hose (from the pump side toward the pool) to clear obstructions.
• Inspect flow sensor: If equipped, locate the flow or pressure sensor connected to the Calpeda controller. Ensure its ports are not clogged with scale or debris. Clean gently and reinstall.
• Reset dry-run alarm: After restoring proper flow, reset the controller and test. If E04 persists with good flow, the sensor or controller may be faulty and require replacement.