BoilerFaultCodesRavenheat 28 Fault Code
The Ravenheat 28 fault code means: your boiler has detected that there is not enough water pressure or flow to operate safely, which is preventing your heating and hot water from working.. It appears on 8 Ravenheat models in our database.
Technical description: Failed low water – pressure switch or pump, possible issue with pump, incorrect system pressure or the low water switch pressure needs replacing
What causes the Ravenheat 28 fault?
This fault occurs when the boiler's internal sensors detect that water is not circulating correctly or the pressure has dropped too low to operate safely. The most common reason is a simple loss of water pressure in the central heating system, but it can also be caused by a mechanical failure of the pump or a faulty sensor that is incorrectly reporting low pressure.
This issue often surfaces when the heating is turned back on for autumn, as stagnant pumps can seize or system pressure may have dropped during a summer of inactivity.
DIY fix possible
Check the pressure gauge on the front of the boiler; it should be between 1.0 and 1.5 bar.If the pressure is too low, use the external filling loop to top up the system with water.Ensure all radiator valves are open and bleed any air from the radiators.Turn the boiler off and back on again to reset the fault.
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Gas Safe Register →Ravenheat models that show the 28 fault code
Click a model for the full fault code list and model-specific repair notes.
Source
Ravenheat 28 fault code information on this page is sourced and cross-checked against the official Ravenheat service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026