Furnace display shows low water pressure; burner does not start (for IVT hydronic furnace/boiler models)

Safety: Turn off power and allow the hydronic system to cool before adding water. Hot water under pressure can cause scalding.

• Check system pressure gauge: On IVT hydronic furnaces, verify the pressure reading. Typical cold fill pressure is around 1.0–1.5 bar (check your manual).
• Top up system: Locate the filling loop or automatic fill valve. Slowly open the valve and watch the pressure gauge rise to the recommended level, then close the valve completely.
• Inspect for leaks: Walk the system piping and radiators, looking for visible water leaks, stains, or dripping valves. Repair any leaks before refilling again.
• Reset the unit: After pressure is restored, reset the IVT control and call for heat. If the code persists despite correct pressure, the pressure sensor or its wiring may be defective.

If you are unsure how to use the filling loop or if pressure drops repeatedly, contact a qualified hydronic heating technician.