Service Type: No Heat – Furnace Diagnosis Equipment: Gibson Mid-Efficiency Furnace Client Concern: Furnace not heating; unit displaying limit open error code. Inspection & Findings: - Furnace found in error code mode indicating limit open. - Checked all limit switches and entire limit circuit electrically; all components tested correctly and ohmed out within specifications. - Determined issue is most likely related to the circuit board. - Removed circuit board and inspected for visible damage or burn marks; none observed. - Reinstalled circuit board and furnace resumed normal operation. - Performed further diagnostic testing; no additional faults found at this time. - Due to age of furnace, circuit board malfunction remains a concern and may recur. Recommendations: - Due to age of equipment and high cost of circuit board replacement, furnace replacement is recommended as the more reliable long-term solution. - Discussed replacement furnace options with client, including multiple bra