Ideal Falcon Gte Fault codes & diagnostics

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

Regular Natural Gas 20.5-35.1 kW 2000-2005 Discontinued

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Severity at a glance

Each cell = one fault code. Hover to identify.
9 High 2 Low
Just want the most common Ideal Falcon Gte 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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B4

Your boiler is currently running at a low power level to maintain heat efficiently, which is a normal status indicator rather than a breakdown.

Low DIY-safe

What to check first

  1. Check if the heating or hot water is reaching the desired temperature
  2. Observe the display to see if the code changes as demand increases
  3. No action is required as this is an operational status message

Related codes

Full explanation for B4
B5

Your boiler is working at its higher power setting to meet a heavy demand for heating or hot water, and everything is functioning as it should.

Low DIY-safe

What to check first

  1. No action is required as this is an operational status message rather than a fault.
  2. Monitor the boiler to ensure it returns to standard operation once the demand for heat reduces.

Related codes

Full explanation for B5
L1

Your boiler has likely overheated or a safety sensor has detected an electrical fault, causing the system to shut down for safety.

High DIY-safe £120-£350

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure your boiler pressure is between 1.0 and 1.5 bar
  3. Press and hold the reset button for 2 seconds

Parts commonly replaced

  • Overheat Thermostat
  • Internal Pump
  • Main PCB
Full explanation for L1
S3

Your boiler's burner has shut itself down for safety because it failed to light or stay lit correctly.

High DIY-safe £120-350

What to check first

  1. Check that your gas or oil supply is turned on and you have credit on your meter.
  2. Locate the reset button on the burner control box and press it once.
  3. Check for any obvious blockages in the flue pipe outside.

Parts commonly replaced

  • Ignition electrode
  • Photocell (Flame sensor)
  • Burner control box
  • Fuel pump
Full explanation for S3
T1/T2

Your boiler's internal thermostat or control wiring has lost connection, preventing the heating from firing up.

High Engineer only £120-250

Parts commonly replaced

  • Boiler thermostat
  • Wiring harness
  • Control PCB
Full explanation for T1/T2
T6

Your boiler is struggling to switch to its high-power mode because of an electrical signal failure in its temperature control system.

High Engineer only £120-£350

Parts commonly replaced

  • High-limit thermostat
  • Wiring harness
  • Control PCB
Full explanation for T6
T7

Your boiler has shut down because a specific safety thermostat has detected that the burner is not modulating correctly or is incompatible with the control settings.

High Engineer only £120-280

Parts commonly replaced

  • Modulating Burner Controller
  • Safety Thermostat
  • Main PCB

Related codes

Full explanation for T7
T8

Your boiler is struggling to switch to its high-power mode because of an electrical signaling issue within its internal control system.

High Engineer only £150-350

Parts commonly replaced

  • Main PCB
  • Burner control wiring loom
  • Stage 2 thermostat relay

Related codes

Full explanation for T8
V/J

Your boiler has detected an issue with its electrical grounding or wiring, which is a safety mechanism that prevents electrical faults.

High Engineer only £90-250

Parts commonly replaced

  • Main PCB
  • Wiring Harness
  • Earth electrode
Full explanation for V/J
VA

Your boiler has failed to ignite or stay lit, meaning your heating and hot water have stopped working to protect the system.

High DIY-safe £100-£350

What to check first

  1. Check if your gas supply is active (e.g., check other gas appliances or your meter credit)
  2. Press and hold the 'Reset' button for 3 seconds
  3. Ensure the condensate pipe (the white plastic pipe outside) hasn't frozen in cold weather

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • PCB (Printed Circuit Board)
  • Flame Sensing Probe
Full explanation for VA
VA-TS

Your boiler has switched itself off because it has detected that the water inside has become dangerously hot.

High DIY-safe £120-£350

What to check first

  1. Check that all radiator valves are fully open to allow water flow
  2. Inspect the system pressure gauge and top up to 1.5 bar if it is too low
  3. Press the reset button on the front control panel to restart the boiler

Parts commonly replaced

  • Overheat Thermostat (Limit Stat)
  • Circulation Pump
  • Thermistor (NTC Sensor)
Full explanation for VA-TS