F7 code, fan runs continuously even when no hot water is demanded

Safety first: Turn off power and gas. Continuous fan operation can indicate a control fault.

• Inspect wiring: Verify that the blower motor is wired exactly as per the Giant wiring diagram. Look for any recent splices or mis‑wired connections.
• Check control board: With power off, inspect the control board for signs of overheating or burned relay contacts.
• Test operation: Restore power briefly and observe whether the blower starts immediately without a call for heat. If so, the blower relay is likely stuck closed.
• Replace control board: Replace the Giant electronic control board if the blower relay is stuck. This repair is best performed by a qualified technician.