Biasi Riva Compact HE M96a Fault codes & diagnostics

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

Combi Natural GasLPG 24-28 kW 2008-2012 Discontinued

Replaced by: Advance Plus

Download the Biasi Riva Compact HE M96a manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
5 Emergency 31 High 1 Medium
Just want the most common Biasi Riva Compact HE M96a faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 37 documented codes

Tap any card for details

LED / flash-pattern codes
Flashing LD2

Your boiler is struggling to detect water moving through the system, which prevents it from safely turning on your heating or hot water.

High DIY-safe £120-250

What to check first

  1. Check your boiler pressure gauge and ensure it is between 1.0 and 1.5 bar
  2. If the pressure is low, use the filling loop to top it up to the correct level
  3. Turn the boiler off and back on again to clear the electronic fault

Parts commonly replaced

  • Primary flow switch
  • NTC Temperature sensor
  • Circulation pump

Related codes

Full explanation for Flashing LD2
LD1, LD2 Flashing

Your boiler is struggling to detect the temperature of your hot water, which likely means you will have no hot water from your taps.

High Engineer only £120-200

Parts commonly replaced

  • DHW NTC Temperature Sensor

Related codes

Full explanation for LD1, LD2 Flashing
LD1, LD2, LD3 Flashing

Your boiler's temperature sensor is providing incorrect readings, which prevents the unit from heating your water correctly.

High Engineer only £120-200

Parts commonly replaced

  • Central Heating NTC Temperature Sensor
Full explanation for LD1, LD2, LD3 Flashing
LD2, LD3 Flashing

Your boiler has detected an issue with the sensor that monitors the temperature of the exhaust fumes, meaning it has switched itself off to prevent overheating.

High Engineer only £150-250

Parts commonly replaced

  • Flue NTC Sensor
  • Wiring harness

Related codes

Full explanation for LD2, LD3 Flashing
Operation lights flashing

Your boiler is starting up briefly but then switching itself off because it is struggling to safely expel waste gases or drain excess condensation.

High DIY-safe £100-280

What to check first

  1. Check the white plastic condensate pipe outside for signs of freezing or blockages
  2. Thaw a frozen external pipe using warm (not boiling) water or a heat pack
  3. Ensure the external flue terminal is not obstructed by debris, snow, or vegetation

Parts commonly replaced

  • Air Pressure Switch
  • Condensate Trap
  • Fan Assembly
  • Venturi Tube
Full explanation for Operation lights flashing
Red Led Flashing

Your boiler is failing to light the gas flame despite several attempts, causing it to shut down for safety.

High DIY-safe £100-280

What to check first

  1. Check if other gas appliances, like a cooker hob, are working to ensure gas supply is active.
  2. Verify that your gas meter has credit if you use a pre-payment meter.
  3. Press the reset button on the front panel once to see if the boiler restarts.

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Printed Circuit Board (PCB)
Full explanation for Red Led Flashing
Digital codes
A fault on gas supply

Your boiler has stopped working because it cannot detect a steady supply of gas or a flame.

High DIY-safe £100-350

What to check first

  1. Check if other gas appliances, like a cooker, are working to confirm gas supply to the house.
  2. Verify that your gas meter has credit if it is a pre-payment type.
  3. Locate the reset knob on the front panel and turn it to the 'R' position for a few seconds.

Parts commonly replaced

  • Gas Valve
  • Ignition Electrode
  • Flame Sensing Electrode
  • Printed Circuit Board (PCB)
Full explanation for A fault on gas supply
All operation lights OFF

Your boiler appears to have no power and is completely unresponsive when you try to use your heating or hot water.

High DIY-safe £100-350

What to check first

  1. Check if the boiler's fused spur switch is turned on
  2. Check your home's main consumer unit (fuse box) for a tripped circuit breaker
  3. Replace the 3-amp fuse in the boiler's external electrical spur

Parts commonly replaced

  • External 3A Fuse
  • Printed Circuit Board (PCB)
  • Internal Glass Fuse
Full explanation for All operation lights OFF
E00---684

Your boiler is failing to detect that water is circulating properly, which prevents it from firing up to heat your home or provide hot water.

High Engineer only £150-250

Parts commonly replaced

  • Flow switch
  • Diverter valve cartridge
  • Central heating pump

Related codes

Full explanation for E00---684
E00---688

Your boiler is not detecting the flow of water needed to start the heating or provide hot water, likely because an internal sensor is stuck or blocked.

High Engineer only £150-250

Parts commonly replaced

  • Diverter valve diaphragm
  • Flow switch microswitch
Full explanation for E00---688
Showing 11–20 of 37
E01---204

Your boiler is struggling to detect or produce hot water, meaning you currently have no hot tap water available.

High Engineer only £150-250

Parts commonly replaced

  • DHW Flow Switch
  • Secondary Heat Exchanger
  • DHW Sensor

Related codes

Full explanation for E01---204
E01---205

Your boiler is struggling to detect or regulate the flow of hot water, which usually means the system that transfers heat to your taps has become blocked or faulty.

High Engineer only £180-350

Parts commonly replaced

  • DHW plate heat exchanger
  • DHW flow sensor
  • Diverter valve

Related codes

Full explanation for E01---205
E83---013

Your boiler has detected that the water pressure inside the system has become too high, triggering a safety mechanism to prevent damage.

High Engineer only £120-250

Parts commonly replaced

  • Pressure Relief Valve (PRV)
  • Expansion Vessel
  • Filling Loop
Full explanation for E83---013
E83---082

Your boiler is failing to detect that you have turned on a hot water tap, meaning it won't fire up to heat the water for your shower or washbasin.

Medium Engineer only £120-220

Parts commonly replaced

  • DHW flow switch
  • Flow turbine sensor
Full explanation for E83---082
E83---086

Your boiler is struggling to switch between heating your radiators and heating your hot water because a motorised part inside has failed.

High Engineer only £180-350

Parts commonly replaced

  • Diverter valve actuator
  • Diverter valve cartridge
Full explanation for E83---086
E83---101

Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage or danger.

High Engineer only £120-250

Parts commonly replaced

  • Overheat thermostat
  • Pump
  • Diverter valve
  • Heat exchanger
Full explanation for E83---101
E83---121

Your boiler is struggling to manage the water pressure inside the system because the internal vessel responsible for absorbing pressure changes is no longer functioning correctly.

High Engineer only £180-350

Parts commonly replaced

  • Expansion Vessel
  • Pressure Relief Valve
Full explanation for E83---121
E83---122

Your boiler is failing to detect the flame correctly during ignition, causing it to shut down for safety reasons.

High Engineer only £120-220

Parts commonly replaced

  • Ignition electrode
  • Flame rectification probe
  • Ignition lead
Full explanation for E83---122
E83---126

Your boiler is failing to ignite because it cannot detect the flame required to get your heating or hot water started.

High Engineer only £120-220

Parts commonly replaced

  • Ignition electrode
  • Ignition lead
  • PCB

Related codes

Full explanation for E83---126
E83---127

Your boiler is failing to light the flame because the sensor responsible for detecting or starting the spark is not working as expected.

High Engineer only £120-220

Parts commonly replaced

  • Ignition electrode
  • Ignition lead
  • PCB

Related codes

Full explanation for E83---127
Showing 21–30 of 37
E83---129

Your boiler has detected an issue with the fuel supply system, meaning it cannot ignite or maintain the flame required to produce heat or hot water.

High Engineer only £180-350

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)
  • Wiring harness
Full explanation for E83---129
E83---142

Your boiler is failing to light the flame properly, which means it cannot provide you with any heating or hot water until the issue is repaired.

High Engineer only £150-300

Parts commonly replaced

  • Ignition electrode
  • Ignition lead
  • PCB

Related codes

Full explanation for E83---142
E83---178

Your boiler has detected an issue with the internal panels surrounding the combustion area, which is a safety mechanism to ensure the unit is sealed correctly.

Emergency Engineer only £150-250

Parts commonly replaced

  • Combustion chamber insulation panels
  • Flue gas sensor
Full explanation for E83---178
E83---180

Your boiler has detected an issue with the internal insulation panel inside the combustion chamber, which is a vital safety component for containing heat.

Emergency Engineer only £150-250

Parts commonly replaced

  • Combustion chamber rear insulation panel
  • Insulation kit
Full explanation for E83---180
E83---181

Your boiler has detected an issue with the insulating material inside the sealed metal box where the fire burns, which is preventing it from operating safely.

Emergency Engineer only £150-250

Parts commonly replaced

  • Combustion chamber rear panel insulation
  • Insulation kit
Full explanation for E83---181
E83---196

Your boiler has detected an issue with the seal or attachment of the front cover to the combustion chamber, which is a safety-critical area that keeps exhaust fumes contained.

Emergency Engineer only £120-220

Parts commonly replaced

  • Combustion chamber seal kit
  • Front panel clips
Full explanation for E83---196
E83---197

Your boiler has detected that the front cover of its internal combustion area is loose or not sealed properly, which prevents it from operating safely.

Emergency Engineer only £120-250

Parts commonly replaced

  • Combustion chamber seal
  • Front panel retaining clips
  • Pressure switch assembly
Full explanation for E83---197
Faulty flame detection

Your boiler is struggling to confirm that the burner has lit correctly, so it has shut down as a safety precaution.

High Engineer only £120-220

Parts commonly replaced

  • Flame detection electrode
  • Ignition lead
  • Printed Circuit Board (PCB)
Full explanation for Faulty flame detection
Faulty ignition

Your boiler is struggling to light the gas, which means you won't have any heating or hot water until the ignition system is fixed.

High Engineer only £120-240

Parts commonly replaced

  • Ignition electrodes
  • Ignition lead
  • Printed Circuit Board (PCB)
Full explanation for Faulty ignition
Faulty modulation gas valve

Your boiler is unable to control the flow of gas correctly, which means it cannot fire up to provide heating or hot water.

High Engineer only £180-320

Parts commonly replaced

  • Gas Valve
  • Printed Circuit Board (PCB)
  • Wiring Harness
Full explanation for Faulty modulation gas valve
Showing 31–37 of 37
Faulty primary circuit

Your boiler has stopped working because it cannot detect enough water circulating inside the system to keep it running safely.

High DIY-safe £100-250

What to check first

  1. Check your boiler pressure gauge to see if it is below 1.0 bar
  2. Locate the filling loop (a silver flexi-hose or two taps underneath the boiler)
  3. Slowly open the valve to allow water into the system until the gauge reaches 1.5 bar, then turn the valve fully off

Parts commonly replaced

  • Circulation pump
  • Flow sensor
  • Heating system pressure gauge
Full explanation for Faulty primary circuit
Gas injectors blocked

Your boiler has stopped working because the gas burners are clogged and cannot ignite the fuel properly.

High Engineer only £90-180

Parts commonly replaced

  • Gas Injectors
  • Burner Assembly
  • Gas Valve
Full explanation for Gas injectors blocked
Lack of burner ignition

Your boiler is trying to start up but cannot create or detect a flame, leaving you without heating and hot water.

High DIY-safe £120-350

What to check first

  1. Check that your gas emergency control valve is open and you have credit on your meter.
  2. Check if other gas appliances in your home, like a hob, are working correctly.
  3. Press the reset button on the front control panel to see if the boiler restarts.

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Printed Circuit Board (PCB)
  • Flame Sensing Electrode
Full explanation for Lack of burner ignition
lock-out signal lamp

Your boiler has stopped working for safety reasons and needs to be manually restarted to attempt to fire up again.

High DIY-safe £100-350

What to check first

  1. Locate the reset button (often marked with an 'R' or a flame symbol) on the boiler control panel.
  2. Press and hold the reset button for 2 to 5 seconds.
  3. Wait for the boiler to attempt the ignition sequence; if it fails to start after three attempts, call a Gas Safe engineer.

Parts commonly replaced

  • Ignition Electrode
  • Printed Circuit Board (PCB)
  • Gas Valve
Full explanation for lock-out signal lamp
Lock-out signal lamp ON

Your boiler is failing to detect that the flame has lit, causing it to shut down for safety reasons to prevent a build-up of unburned gas.

High Engineer only £150-250

Parts commonly replaced

  • Flame rectification electrode
  • Ignition lead
  • Printed Circuit Board (PCB)
Full explanation for Lock-out signal lamp ON
Lock-out signal lamp red

Your boiler is failing to light the flame properly and has safely shut itself down to prevent a gas build-up.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
Full explanation for Lock-out signal lamp red
Lock-out signal lamp red (ON)

Your boiler is failing to detect the flame after lighting, causing it to shut down for safety even though the burner briefly ignites.

High Engineer only £120-250

Parts commonly replaced

  • Flame sensing electrode
  • Ignition lead
  • PCB
Full explanation for Lock-out signal lamp red (ON)
Status & diagnostic codes

10 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

Flashing LD1 Status Your boiler is operating normally and performing a standard system check, so there is no fault to be concerned about. 1 second ON / 1 second OFF Status Your boiler is operating normally and is currently waiting for a command to provide heating or hot water. 1 second ON 1 second OFF Status Your boiler is currently operating normally and is simply indicating that it is actively heating your radiators or hot water. A short pulse every 4 seconds Status Your boiler is currently switched off but is working correctly to protect itself from freezing during cold weather. C.h. operation Status Your boiler is currently operating normally in central heating mode with no active faults indicated. D.h.w. operation Status Your boiler is signalling that it is currently trying to heat your domestic hot water as expected. E01 Diagnostic Your boiler has failed to ignite or stay lit, which means it cannot produce hot water or heating. Frost protect operation Status Your boiler is temporarily running its pump to prevent your pipes from freezing during cold weather. Normally operating boiler Status Your boiler is operating normally and is currently in standby mode, waiting for a signal to provide heating or hot water. ON Status Your boiler is operating normally and is currently responding to a request for heating or hot water.