Display shows bYP or BYPASS ONLY; system refuses to send water to solar panels.

Safety: No plumbing work is required for this check, but always be cautious around live electrical equipment.

• Check mode setting: On the Fafco controller front panel, verify the mode is set to AUTO or HEAT, not SERVICE or BYPASS. Change to AUTO and observe operation.
• Inspect manual override: Some Fafco controllers have a physical toggle or dip switch for bypass. Ensure it is in the normal operating position.
• Review temperature conditions: If the roof sensor is colder than the pool or near freezing, the controller will intentionally bypass. Confirm actual temperatures and wait for warmer conditions.
• Freeze protection: If freeze protection is enabled, the system may run in bypass to protect plumbing. Verify freeze settings in the controller menu.
• Power-cycle: Turn the controller off for 30 seconds and back on to clear any latched bypass state, then test again.