Boiler displays E17 and indicates pump or circulation error

Safety: Turn off power and allow the system to cool. Be prepared for hot water when opening pump vents.

• Check pump operation: During a call for heat, place a hand on the primary pump body. You should feel vibration and slight warmth. If it is silent and cold, it may not be running.
• Bleed pump: Some circulators have a vent screw on the front. With a towel ready, carefully loosen the screw to release trapped air until water flows steadily, then retighten.
• Inspect wiring: Verify the pump is properly wired to the Dettson control and that connectors are tight.
• Professional testing: A technician should check for voltage at the pump terminals when the boiler calls for circulation. If voltage is present but the pump does not run, replace the Dettson primary circulator. If no voltage, the control board or relay may be faulty.