Ideal F2: overheat protection on a Logic combi
F2 trips when the primary circuit temperature climbs past the appliance's safe ceiling. The boiler is protecting the heat exchanger from damage, so treating it as a nuisance to reset repeatedly is the wrong approach.
Where an F2 overheat fault usually comes from
Restricted flow is the leading cause: a stuck zone valve, a failing pump, or a system choked with corrosion debris all stop heat escaping the exchanger fast enough. A faulty overheat thermostat or flow sensor can trip the same code with a perfectly healthy system, which is why flow is measured directly rather than assumed. Fixing the true circulation fault stops the code recurring under load.
Things worth knowing about an F2 overheat fault
- Flow restriction is the leading cause, not the sensor
- A stuck zone valve produces identical symptoms to a failing pump
- System debris chokes flow gradually before F2 appears suddenly
- Flow is measured directly rather than judged by feel
- A genuinely faulty stat trips F2 on an otherwise healthy system
Where we deal with this
Who should undertake the work
- Gas appliance work must be completed by a suitably qualified Gas Safe engineer
- Oil appliance work should be completed by a suitably qualified OFTEC technician
- Jamie Crawford Heating states both Gas Safe and OFTEC registration
Book a visit for an F2 overheat fault
Our advice: F2 is about heat escaping, not heat being produced. Fix the circulation path and the overheat trips stop.
Jamie Crawford Heating is based at 24 Bristol Road, Radstock, BA3 3EE.
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Services that cover this
Questions we get asked
- Is F2 the same as an EA-style ignition fault?
- No — F2 is a temperature fault after the boiler has already been running, not a flame-detection issue.
- Will a filter prevent this?
- A magnetic filter reduces debris-driven restriction, which is one of several possible causes.
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