Biasi Parva 28S Fault codes & diagnostics

10 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

System Natural Gas 28 kW Discontinued

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Severity at a glance

Each cell = one fault code. Hover to identify.
10 High
Just want the most common Biasi Parva 28S faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 10 documented codes

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30c

Your boiler has likely detected a sensor problem that is preventing it from heating your water correctly.

High Engineer only £90-180

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness
  • Main PCB
Full explanation for 30c
ER + 14 + Reset

Your boiler has failed to ignite after several attempts, meaning it cannot provide heating or hot water until it is checked.

High Engineer only £100-£250

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Flame Sensing Electrode
Full explanation for ER + 14 + Reset
ER + 25 + Reset

Your boiler has likely detected a circulation or temperature sensor problem and is currently locked out for safety.

High DIY-safe £120-280

What to check first

  1. Locate the selector knob on the front panel.
  2. Turn the knob to the 'Reset' position for five seconds.
  3. Return the knob to the original setting (Heating or Hot Water) and wait for the boiler to restart.

Parts commonly replaced

  • NTC Temperature Sensor
  • Circulation Pump
  • Main PCB
Full explanation for ER + 25 + Reset
ER + 69

Your boiler has detected an electrical communication problem or a wiring fault within its internal control system.

High Engineer only £120-350

Parts commonly replaced

  • Main PCB
  • Wiring Harness
Full explanation for ER + 69
ER 01 + Reset

Your boiler has failed to ignite or has lost its flame, meaning it has shut down as a safety precaution.

High DIY-safe £100-£250

What to check first

  1. Check that your gas supply is turned on at the meter
  2. Press and hold the 'Reset' button for five seconds
  3. Ensure there is credit on your gas meter if you use a pre-payment system

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Gas Valve
Full explanation for ER 01 + Reset
ER 02 + Reset

Your boiler has detected that it is getting too hot and has shut down as a safety precaution.

High DIY-safe £100-£350

What to check first

  1. Ensure all radiator valves are fully open to allow water to circulate
  2. Check that the boiler pressure is between 1.0 and 1.5 bar
  3. Press and hold the 'Reset' button to restart the system

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • NTC Temperature Sensor
Full explanation for ER 02 + Reset
ER 03 + Reset

Your boiler has detected a problem with how it clears exhaust fumes or takes in fresh air, causing it to shut down for safety.

High Engineer only £100-280

Parts commonly replaced

  • Fan
  • Air Pressure Switch
  • Venturi Tube
Full explanation for ER 03 + Reset
ER 10 + reset

Your boiler has detected low water pressure, which prevents it from firing up to provide heating or hot water.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver flexible hose) underneath the boiler.
  2. Slowly open the valves until you hear water flowing and the pressure gauge reaches between 1 and 1.5 bar.
  3. Close the valves tightly and press the Reset button to restart the boiler.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel
Full explanation for ER 10 + reset
Li

Your boiler has failed to ignite after several attempts, meaning it cannot produce heat or hot water.

High DIY-safe £100-280

What to check first

  1. Check if other gas appliances like a hob are working to ensure gas supply
  2. Press and hold the reset button for five seconds
  3. Check that the condensate pipe outside hasn't frozen in cold weather

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • PCB (Printed Circuit Board)
Full explanation for Li
LP

Your boiler has detected that the water pressure is too low to operate safely.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop valves underneath the boiler.
  2. Slowly open both taps to let fresh water into the system.
  3. Watch the pressure gauge and close the taps once the needle reaches between 1 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Water pressure switch
  • Expansion vessel
Full explanation for LP