Pump is difficult to prime and frequently loses prime after stopping.

Safety: Turn off the pump before tightening unions or opening lids.

• Tighten unions: Hand‑tighten suction unions at the pump and any nearby fittings. Do not overtighten plastic threads.
• Inspect for cracks: Look for hairline cracks in the suction pipework and fittings, especially near glued joints.
• Check valves: Inspect any Certikin three‑way or isolation valves on the suction for leaks around the spindle or body.
• Replace O‑ring: Fit a new Certikin pump lid O‑ring if the existing one is flattened or perished.