Boiler display shows E10, no heat, circulator may not run

Safety: Turn off power before accessing sensors or control wiring.

Steps:

• 1. Locate supply sensor: On many Slant/Fin boilers, the sensor is inserted into a well on the supply header or attached to the supply pipe with a clamp.
• 2. Check mounting: Ensure the sensor is fully inserted into the well or firmly clamped to the pipe with thermal paste if required.
• 3. Inspect wiring: Follow the sensor leads back to the control board. Tighten any loose terminal screws and reseat plug-in connectors.
• 4. Visual damage: Replace the sensor if the cable insulation is cracked, melted, or cut.

Professional testing: A technician can measure sensor resistance at known temperatures and compare to Slant/Fin specifications to confirm failure and replace with the correct part.