Display shows HPC or HIGH PRESSURE; solar heating shuts down and bypasses panels.

Safety: Turn off pumps and relieve system pressure before loosening any unions or fittings.

• Verify valve positions: Ensure the solar return valve from the Fafco panels to the pool is fully open. A closed or partially closed valve will spike pressure.
• Inspect hoses and pipes: Walk the solar plumbing route, especially flexible hoses to the roof. Look for kinks, crushed sections, or collapsed hoses that restrict flow.
• Check for obstructions: If accessible, disconnect a union near the return from the panels and briefly run water to confirm strong flow. Debris or scale may be lodged in fittings.
• Examine high-pressure switch: Locate the high-pressure switch on the Fafco manifold. Inspect for leaks, corrosion, or damaged wiring. If pressure is normal on a gauge but HPC persists, the switch may be stuck.
• Replace faulty components: Install a new Fafco-compatible high-pressure switch or repair blocked piping as needed, then reset the controller and test.