Responded to a no heat complaint in a vacant property with furnace short cycling due to overheating. Diagnosed multiple issues: inducer draft motor failing and causing improper exhaust ventilation, incorrectly sized filter boot restricting proper airflow, and excessive gas pressure in low fire (over 2" wc, above the 1.3"-1.7" manufacturer range). Adjusted gas pressure down to 1.38" wc, removed filter, and restored proper heat operation with extended run cycles.
