Heater leaks only when pump is off; water drips slowly from plumbing connections

Safety: Turn off power to the heater and pump. Close isolation valves if present.

• Tighten unions: Hand-tighten the inlet and outlet unions on the SunHeater. Do not overtighten; use only a small additional turn with a strap wrench if needed.
• Replace O-rings: Disassemble the unions and inspect the Union O-Rings. Replace any flattened, cracked, or brittle O-rings and lubricate lightly with silicone pool lube before reassembly.
• Inspect PVC fittings: Look for hairline cracks in the PVC elbows or couplings near the heater. Replace any damaged fittings and allow glue joints to cure fully before pressurizing.
• Retest: Restore water flow and check for leaks under pressure and when the pump is off.