Display shows E05 and furnace will not fire, often associated with low system pressure or air in system.

Safety: Allow the system to cool before topping up water. Do not over-pressurise the system. Check for visible leaks before adding water.

User checks (if your Ravenheat unit is part of a sealed hydronic system):

• Check the pressure gauge on the front of the unit. If below the recommended cold pressure (typically around 1.0–1.5 bar, check your manual), use the filling loop to top up slowly.
• Bleed radiators or air vents to remove trapped air, then re-check pressure.
• Reset the appliance and see if E05 clears.

Technician checks:

• Inspect for leaks at radiators, valves, and around the furnace/boiler casing.
• Test the water pressure sensor for correct resistance/voltage output and replace if faulty.
• Check for blockages in the system filter, magnetic filter, or primary heat exchanger.
• Verify correct pump operation and that isolation valves are fully open.

If pressure repeatedly drops after topping up, a leak or expansion vessel fault is likely and must be professionally addressed.