York YP9C five red flashes: flame where the control did not ask for it

What Does Error 5 red flashes Mean?

Five red flashes on a York YP9C control reports flame present at a time the control did not command it. That is a statement about the gas train rather than about ignition performance, so the furnace should be taken out of use and handed to a licensed engineer rather than reset and observed. Applies to: York YP9C modulating condensing gas furnaces documented in the York installation manual The flash table referenced here is the one published for the York YP9C modulating condensing furnace. York assigns flash counts differently across its furnace lines, and equipment from related brands on similar control platforms carries its own table, so the model on the rating plate governs. Owner-safe checks: Check for any smell of gas first, and if one is present leave the property and call the gas emergency number from outside before anything else. | Isolate the appliance using the service switch fitted beside it, which ends the cycling without touching anything inside the cabinet. | Write down whether continued warmth or burner activity was observed, and at what point in the cycle the flashes appear. Qualified technician: Gas valve testing, burner inspection, and flame sensing circuit measurement on a modulating condensing furnace are licensed gas engineering tasks. | Do not restore the furnace to service to see whether the code returns. A repeat cycle is the risk this code is warning about.

Other Common York furnace — York YP9C modulating condensing gas furnaces documented in the York installation manual Error Codes