Work Performed: Responded to no heat call. Furnace displaying error code E207 — “Hot Surface Igniter Sensed Open.” Verified power, ground, and low-voltage circuits. Hot surface igniter tested at 48 ohms, which is within manufacturer specifications, and glows properly on startup attempts. However, the furnace does not begin a full heating sequence and immediately faults with code E207. Removed and cleaned wiring connections on the circuit board, cleaned inside the furnace cabinet and burner area, and ensured proper grounding. After these steps, the furnace briefly fired up a few times but consistently faulted again with code E207 within a minute. Consulted manufacturer diagnostic manual — after all recommended troubleshooting steps, the fault is determined to be internal to the control board (likely start relay failure or internal board fault). Recommendation: - Replace circuit board. We will send repair estimate. - After replacement, complete full furnace diagnostic, s