Ran a call this morning with an 80% single-stage short-cycling every about 3 minutes; limit was opening at 195°F with total external static at 0.92" wc (UEI manometer) thanks to a matted return filter and a few closed bedroom dampers… My rule: verify airflow first — static and temp rise against the plate — before chasing boards or gas valves; saves me 30 minutes easy. What’s your quickest first two checks on short-cycle complaints?
On calls like that I’ll ‘pop the blower door’ for 30–60 seconds and watch temp rise/limit — if it holds, you’ve proved a starved return and it sells the airflow fix without chasing boards. Only as a quick diagnostic though; if it doesn’t change, I pivot to checking the coil face before touching the heat tap.
But had one last week: after filter/dampers, it still hit limit — the blower wheel was wearing a fur coat and the heat tap was low; cleaned it and bumped to med-high, temp rise landed on the plate. If it’s still hot after airflow fixes, clock the meter to rule out overfire before blaming a board, @mark_ste78.