Compare what each person actually checked
Read the original heating section, including limits and recommendations. Ask the later technician for the exact condition, its location, and the evidence supporting it. Did the later visit examine an area the home inspector did not evaluate? Does it report a new condition, or does it merely give a different interpretation of the same evidence?
We recommend placing both reports in front of the second evaluator. Ask that person to address the specific condemned finding using the furnace model's applicable procedure. A new report that says only “heat works” will not resolve a reported internal defect.
What makes a second opinion useful?
It should say whether the finding is confirmed, disproved, or remains unresolved, and explain why. Ask which areas were inspected and which were inaccessible. If the furnace must remain off, ask what repair or replacement can address the condition and who is responsible for clearance after the work.
Do not assume the later contractor is wrong because the diagnosis arrived soon after a home purchase. Do not assume the home inspector was negligent from the timing alone. The question can be resolved only by matching each conclusion with the visit's scope and evidence.
If your question also concerns an inspection contract or seller disclosure, keep those records and seek advice from the appropriate party. That is separate from deciding whether the furnace may operate now.
The next step is to request both written reports and an equipment-specific review. This gives you a way to understand the condition, compare supported work, and pursue any separate transaction question without overriding the current safety restriction.