Heatline Solaris Fault codes & diagnostics

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

Combi Natural Gas 24-30 kW 2006-2010 Discontinued
GC Numbers 47-157-0447-157-05

Replaced by: Capriz

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

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Severity at a glance

Each cell = one fault code. Hover to identify.
10 High 1 Low
Just want the most common Heatline Solaris faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 11 documented codes

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0.8bar

Your boiler has detected that the water pressure is too low for it to operate safely and effectively.

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 one or two taps/valves until you hear water entering the system.
  3. Watch the pressure gauge and close the taps once the needle reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for 0.8bar
F0

Your boiler has stopped working because the water pressure inside the system is too low.

High DIY-safe £0-120

What to check first

  1. Locate the flexible filling loop underneath the boiler.
  2. Slowly open the small valves on the loop until you hear water entering the system.
  3. Watch the pressure gauge and close the valves once the needle reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for F0
F1

Your boiler has automatically shut down for safety because its internal temperature has climbed too high.

High Engineer only £120-250

Parts commonly replaced

  • NTC sensor
  • Primary heat exchanger
  • Pump
  • Overheat thermostat

Related codes

Full explanation for F1
F2

Your boiler is struggling to accurately detect the temperature of your hot water, which means it has stopped heating it up to prevent the system from getting too hot.

High Engineer only £120-220

Parts commonly replaced

  • DHW NTC sensor

Related codes

Full explanation for F2
F3

Your boiler has stopped working because it is unable to accurately measure the temperature of the water inside the system.

High Engineer only £120-220

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness

Related codes

Full explanation for F3
F4

Your boiler is failing to light the flame needed to produce heat or hot water.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Full explanation for F4
F5

Your boiler has detected a fault with a safety sensor that monitors the temperature of the gases leaving your flue, meaning the boiler has shut down to prevent potential overheating.

High Engineer only £150-250

Parts commonly replaced

  • Flue gas temperature sensor
  • Wiring harness

Related codes

Full explanation for F5
F6

Your boiler is having trouble communicating with the outside temperature sensor, which helps it run efficiently based on the weather.

Low DIY-safe £70-130

What to check first

  1. Locate the external sensor on an outside wall to check for obvious physical damage or loose wires
  2. Turn the boiler power off and back on to see if the fault clears
  3. If the issue persists, the boiler will still provide heat but will revert to standard internal settings

Parts commonly replaced

  • External temperature sensor (Outdoor weather compensator)
  • Wiring harness

Related codes

Full explanation for F6
F7

Your boiler is struggling to confirm that the internal fan is spinning correctly, so it has safely shut itself down to prevent any unsafe operation.

High Engineer only £150-250

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

Full explanation for F7
F8

Your boiler has detected that the fan, which safely removes waste gases from your home, is not spinning at the correct speed or has stopped working entirely.

High Engineer only £180-£350

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Air pressure switch

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 up safely.

High Engineer only £150-250

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)

Related codes

Full explanation for F9
Status & diagnostic codes

3 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 adjusting its settings to match the weather outside. S.13 Status Your boiler is failing to light the flame, so it has safely stopped operating to prevent gas from building up inside. S.27 Status Your boiler is simply finishing a final water circulation cycle to safely cool itself down after heating has been running.