Ideal Heating code F2

Ideal F2: the flame was there and then it was not

Ideal F2 records a flame loss during operation rather than a failure to light. See why that distinction changes where an engineer looks first.

Source verifiedBy HVAC Bench Editorial DeskLast reviewed
Direct answer

What this means

Ideal uses F2 for a flame loss condition, which is a different event from a failure to establish flame at all. The burner lit, ran, and then the appliance stopped detecting combustion, so the investigation starts from what changed during operation rather than from what prevented ignition.

Equipment and model context

Ideal Logic and Vogue gas boilers using the F-series and L-series fault codes published by Ideal Heating

  • Logic Combi
  • Logic Max Combi
  • Logic System
  • Vogue Max

Ideal publishes separate fault code lists for its Logic, Logic Max, and Vogue ranges, and the same character can carry different detail across them. Take the code from the display of the appliance in front of you and check it against the Ideal literature for that model rather than a general list.

What you may notice

  • The boiler lights, runs for a period, and then stops with F2 shown rather than failing to light at all.
  • The house or the hot water partially heats before the fault appears, which is what distinguishes it from a lockout at ignition.
  • The fault occurs more readily at high output than at low, or only when several appliances are drawing gas.

Likely causes

  • Gas supply that falls under load can starve the burner once the appliance steps up to a higher firing rate.
  • A flame sensing electrode with a surface deposit can lose the signal as conditions change even though combustion continues.
  • Condensate or a flue condition can disturb combustion part way through a run rather than preventing ignition.

Diagnostic paths

It fails only when the boiler goes to full output

Low-demand operation, such as a single radiator or a short hot water draw, completes normally, while a full heating demand ends with the fault.

Note which demands succeed and which fail. A fault tied to firing rate rather than to time points toward gas supply capacity under load.

It coincides with another gas appliance running

Failures cluster when a gas hob, oven, or fire is in use, and the boiler behaves normally when it has the supply to itself.

Record what else was running each time. Supply capacity shared across appliances is a whole-installation question rather than a boiler repair.

It has been gradually happening more often

The fault appeared occasionally at first and now interrupts a larger share of heating and hot water demands.

Estimate how the frequency has changed month by month. A worsening ratio is characteristic of a sensing surface degrading rather than a sudden failure.

What has to keep being true during a run

Ignition is a moment; combustion is a continuous condition. The appliance rechecks the flame signal throughout the run, so anything that degrades partway through, whether supply, sensing, or the flue, ends the cycle.

  1. IgnitionA single successful event
  2. Initial provingConfirms the flame established
  3. Continuous checkThe signal is watched throughout
  4. LossThe gas valve closes immediately
Flame loss and failure to ignite are different faults
EventWhat succeededWhere an engineer starts
Never lightsNothing past the purgeIgnition, gas valve, and supply presence
Lights then loses flameIgnition and initial provingSupply under load and flame sensing
Lights and runs to completionEverythingNo fault to investigate

Timing is the whole diagnosis

A boiler that never lights and a boiler that lights and then stops look almost identical from a corridor: no heat, a code on the display, an engineer needed. To the engineer they are two different jobs. Ignition failing means the chain up to the point of lighting is broken. Flame loss means that chain works and something else changed while it was running.

Because the code alone does not tell somebody arriving how much heat was produced before the fault, the occupant's account of it carries real weight. How long it ran, whether the house warmed at all, and whether hot water arrived before the stop all establish that the burner genuinely lit.

The supply question a boiler cannot answer alone

A modulating boiler running at low output needs a fraction of the gas it needs at full rate. That means an installation with a marginal supply, an undersized pipe run, or a governor that struggles under total load can serve the appliance perfectly at low fire and fail it at high. The boiler experiences that as a flame that disappeared and reports it accordingly.

Establishing it requires a working gas pressure measurement taken at the appliance with everything running, which is a Gas Safe task and a measurement rather than an inspection. The combi no hot water reference covers the wider symptom set, and the flame sensing explainer describes how the appliance detects the flame it is watching.

Service handoff

What to give the technician

Give the engineer the Ideal model and serial number, the F2 code, how long the boiler ran before stopping, which demands fail, and which other gas appliances were running at the time.

Homeowner safe

Safe homeowner checks

  1. Time how long the boiler runs before the fault appears, and note whether heating or hot water was actually produced.
  2. Record which other gas appliances were in use each time the fault occurred.
  3. Note whether failures happen on small demands, large demands, or both, since the pattern is diagnostic.

Is a reset appropriate?

Ideal permits a reset from the control panel, and a small number of attempts establish whether the fault repeats and at what point. Continuing beyond that adds ignition cycles without adding information.

Stop point

When to call a technician

  • Measuring working gas pressure, testing the flame signal, and inspecting the flue and condensate arrangement are Gas Safe registered tasks.
  • If gas can be smelled, that single fact outranks the fault code entirely. Get everyone out, touch no switches, and telephone the emergency line for your supplier once you are outside.

Questions people ask about this

What is the difference between Ideal F2 and an ignition lockout?

An ignition lockout records that the burner never lit. F2 records that it did light and the flame was then lost, so the ignition chain is known to work and the investigation moves to what changed during the run.

Why does it fail only when the heating is on full?

Higher output needs more gas, so an installation with marginal supply capacity can serve the boiler at low fire and starve it at high. The dependence on firing rate is the clue.

Can a dirty flame sensor cause F2?

A deposit on the sensing surface reduces the signal the appliance reads, which can fall below the accepted level partway through a run. It is one candidate alongside supply and flue conditions.

Evidence record

How this page was checked

official manufacturer support article, service manual · checked 2026-09-15

Every technical claim above was written from primary documentation held in the HVAC Bench evidence record: Ideal Heating technical literature. Where a source limits a definition to certain models, test conditions, or product classes, that limit is repeated here rather than generalised.

Documentation class
official manufacturer support article, service manual
Scope of the definition
Ideal Logic and Vogue gas boilers using the F-series and L-series fault codes published by Ideal Heating
Last checked
2026-09-15