York S1-025-53193-000 Flame Sensor

The York S1-025-53193-000 Flame Sensor is the OEM flame rectification sensor with a 90-degree bend used on York gas furnaces, sold under York's Source 1 replacement-parts numbering. It is the part that tells the furnace the burners are actually lit. Once the hot surface igniter lights the burners, the ignition control board applies a small AC voltage to the flame rod; the flame conducts that current and rectifies it into a DC microamp signal that travels back through the burner ground. As long as the board sees that signal it keeps the gas valve open. If the signal is weak or missing, the board shuts the gas valve within seconds, retries, and eventually goes to lockout.

Construction. The sensor in the photo is a straight metal flame rod passing through a white ceramic insulator, with a flat steel mounting flange that has a single mounting hole for the burner bracket screw, and a male quick-connect spade terminal bent 90 degrees off the ceramic body so the wire lead drops cleanly past the burner box. The ceramic isolates the rod electrically from the bracket, so the only path for the flame signal is the rod, the flame, and the burner ground. York flame sensors are not all the same length or shape, so this number should be matched to the S1-025-53193-000 printed or listed for your furnace rather than to a generic universal rod.

Symptoms and testing. The classic sign of a bad or fouled flame sensor is a furnace that lights, runs for a few seconds, shuts off, and then repeats the sequence before locking out with a flame fault code. Before replacing the part, shut off power and gas, remove the sensor, and look for carbon or oxide buildup, pitting, or a cracked ceramic. A light pass with a fine abrasive pad restores a lightly fouled rod, but a thinned, bent or cracked sensor should be replaced. Measure the flame current in microamps with the furnace running, confirm the burner ground and the terminal connection are tight, and reinstall the new sensor in the same position as the original so the rod sits in the flame path without touching a burner.

Key Benefits

• OEM York Source 1 Part: The same S1-025-53193-000 sensor the furnace shipped with, so rod position and flame signal match the factory design.
• Restores Reliable Ignition: A clean, intact flame rod ends the light-run-shutdown cycle and flame lockout that a failed sensor causes.
• Ceramic-Insulated Rod: The ceramic insulator and steel mounting flange keep the flame signal isolated from the burner bracket.
• Quick-Connect Terminal: The 90-degree spade terminal pushes onto the existing lead, so the swap is a one-screw, one-wire job.

Common Questions

• What does a flame sensor do? It proves the burner flame is present by passing a microamp rectified current through the flame back to the ignition control, which holds the gas valve open only while that signal is present.
• Can I clean the old sensor instead? A lightly fouled flame rod often recovers with a fine abrasive pad. If the rod is pitted or thinned, or the ceramic is cracked, replace it with the S1-025-53193-000.
• How do I confirm this is the right sensor? Match the York number on your original sensor and furnace parts list to S1-025-53193-000, and compare the 90-degree terminal and mounting flange to the photo.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.