Thermostat calls for heat but furnace does not start; no error code on thermostat, but furnace may show its own fault code.

Safety first: Turn off power and gas to the furnace before removing panels. Gas and combustion issues are hazardous.

• Check furnace status light: Look through the sight glass on the Payne furnace for a blinking LED. Count the flashes and refer to the furnace manual for the specific fault.
• Reset power: Turn off the furnace switch or breaker for 5 minutes, then restore power to clear a temporary lockout.
• Inspect air filter and vents: Replace a dirty filter and ensure supply and return vents are not blocked, which can cause high‑limit trips.
• Do not bypass safety switches: If rollout or limit switches are open, do not jumper them. Call a qualified technician to find and correct the root cause.
• Verify thermostat W call: Confirm that the thermostat is actually sending a W call (see previous W1 fault steps). If W is present and the furnace still does not start, the issue is within the furnace.