Heatline Vizo Plus Fault codes & diagnostics

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

Combi Natural Gas 24 kW 2007-2009 Discontinued
GC Number 47-157-14

Replaced by: Capriz2

Download the Heatline Vizo Plus manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
6 High 1 Medium
Versions & GC numbers

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
47-157-14 Vizo Plus 24 2007–2009
Just want the most common Heatline Vizo Plus faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 7 documented codes

Tap any card for details

F1

Your boiler has switched itself off because it has reached an unsafe temperature and needs to cool down before it can be restarted.

High DIY-safe £90-180

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the boiler pressure is between 1 and 1.5 bar on the gauge
  3. Press the reset button once the boiler has cooled down for 20 minutes

Parts commonly replaced

  • Overheat thermostat
  • Circulation pump
  • Thermal fuse

Related codes

Full explanation for F1
F2

Your boiler's hot water sensor has malfunctioned, meaning the system can no longer tell how hot your water is or heat it correctly.

Medium Engineer only £90-£160

Parts commonly replaced

  • DHW Thermistor (NTC Probe)
  • Connecting wiring harness

Related codes

Full explanation for F2
F3

Your boiler's internal thermometer has stopped working correctly, meaning the system can no longer monitor the water temperature and has shut down as a precaution.

High Engineer only £90-160

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring Harness

Related codes

Full explanation for F3
F4

Your boiler has stopped working because it failed to light a flame or the drainage pipe for waste water is blocked.

High DIY-safe £90-280

What to check first

  1. Check if your gas supply is active (e.g., check other gas appliances or your meter credit).
  2. Inspect the external white plastic condensate pipe for signs of freezing or blockages.
  3. Press the 'Reset' button on the boiler control panel once to see if the fault clears.

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Printed Circuit Board (PCB)
  • Condensate Trap

Related codes

Full explanation for F4
F5

Your boiler has shut down because it can no longer safely measure the temperature of the exhaust gases leaving the system.

High Engineer only £120-190

Parts commonly replaced

  • Flue NTC sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for F5
F8

Your boiler is struggling to push air through its system correctly, so it has safely shut itself down to prevent any damage.

High Engineer only £180-350

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Venturi tube

Related codes

Full explanation for F8
F9

Your boiler has detected that the internal air extraction fan is spinning when it should be switched off, which prevents the system from starting safely.

High Engineer only £150-250

Parts commonly replaced

  • Air pressure switch
  • Printed circuit board (PCB)
  • Fan assembly

Related codes

Full explanation for F9
Status & diagnostic codes

1 operating states & engineer diagnostics

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

OC Status Your boiler has detected an outdoor temperature sensor and is automatically adjusting its settings to match the weather outside.