Last updated:
Ideal is one of the most common boiler brands in UK rental properties, so its faults are some of the most frequent call-outs landlords deal with. Many are simple: low pressure, a frozen condensate pipe in a cold snap, or a gas supply problem. This guide explains the common Ideal fault codes, what a tenant can safely check, when you need a Gas Safe engineer, and your legal duties when the heating fails.
Key takeaways
- F1 means low water pressure. A tenant can usually fix it by repressurising to the level in the manual, typically 1 to 1.5 bar.
- F2 means flame loss. Check the gas supply and any prepayment meter credit first.
- Frozen condensate pipes are a common cause of winter lockouts and can often be thawed safely with warm water.
- Only a Gas Safe registered engineer may open the boiler casing or work on gas parts.
- Loss of heating or hot water is an urgent repair, especially for vulnerable tenants.
Common Ideal boiler fault codes
The codes below apply to popular Ideal models such as the Logic range. Codes can differ between models, so always check the user manual for the boiler in your property.
| Code | Meaning | What the tenant can safely do | When to call an engineer |
|---|---|---|---|
| F1 | Low water pressure | Repressurise using the filling loop, following the manual | If pressure keeps dropping, which suggests a leak |
| F2 | Flame loss | Check other gas appliances work, the gas is on at the meter, and a prepayment meter has credit | If the gas supply is fine and the code returns |
| F3 | Fan fault | Restart the boiler once | If the code persists |
| F4 / L4 | Flow thermistor fault | Restart the boiler once | If the code persists |
| L2 | Ignition lockout | Check for a frozen condensate pipe, then press reset once | If it locks out again |
Source: Ideal Heating Logic Combi troubleshooting guide. If the boiler is under warranty, contact Ideal first.
The faults landlords see most
1. Low pressure (F1)
Pressure drops after radiators are bled or when there is a small leak. Show tenants where the filling loop is and how to repressurise, and include a photo of the gauge at the correct level in your tenant handbook. If they have to top up more than once every few weeks, send an engineer to find the leak; a slow leak can damage the boiler and the property.
2. No hot water but heating works
On a combi boiler this often points to the diverter valve or a flow sensor. Check the hot water setting first, then call an engineer. It is not a tenant job.
3. Frozen condensate pipe
Modern condensing boilers drain water through a plastic pipe that often runs outside. In freezing weather it can block and lock the boiler out, sometimes with a gurgling noise. A tenant can pour warm (not boiling) water along the outside section, then reset the boiler. If it keeps happening, ask an engineer to insulate or reroute the pipe, or enlarge it to the recommended size.
4. Kettling and banging noises
Usually caused by limescale or sludge restricting flow through the heat exchanger. A powerflush or chemical clean and a magnetic system filter normally fix it. It is a good sign the system needs attention before a more expensive failure.
5. Leaks
Water under the boiler can come from the pressure relief valve, a failed seal or a corroded component. Ask the tenant to turn off the boiler and isolate the water if it is more than a drip, and send an engineer. Do not let them remove the casing.
6. Thermostat and timer problems
Many “boiler not working” calls are a programmer set wrongly or a wireless thermostat with flat batteries. Ask the tenant to check these first. A simple guide to the controls in the handbook saves call-out fees. See our guide to smart thermostats for HMOs if you want remote control.
Your legal duties when the heating fails
- You must keep the heating and hot water installations in repair, and repair them within a reasonable time of being told. Loss of all heating in winter is an emergency.
- Only a Gas Safe registered engineer may work on gas appliances.
- You must have a gas safety check every 12 months and give the tenant a copy. See our gas safety certificate guide.
- Rooms with a boiler used as living accommodation need a working carbon monoxide alarm. See our CO alarm guide.
- If a repair will take time, provide temporary electric heaters, especially for vulnerable tenants.
Prevent call-outs
- Book an annual service with the gas safety check; Ideal’s warranty normally requires it.
- Fit a magnetic filter and keep inhibitor levels topped up.
- Insulate external condensate pipes before winter.
- Register the boiler for its warranty and keep the paperwork in your property file.
For other brands and general combi problems, see our guides to common combi boiler faults and Vaillant combi boiler faults. If you are weighing up whether boiler cover is worth it, read boiler cover for landlords.
Written by The Landlords Portal Team and updated in November 2026. As an Amazon Associate we earn from qualifying purchases. This is general information. Always follow the manufacturer’s manual and use a Gas Safe registered engineer for any gas work.
Frequently asked questions
What does F1 mean on an Ideal boiler?
Low water pressure. Repressurise the system to the level in the manual, usually 1 to 1.5 bar. If it keeps dropping, call a Gas Safe engineer to check for a leak.
What does F2 mean on an Ideal boiler?
Flame loss. Check that the gas is on at the meter, other gas appliances work and any prepayment meter has credit. If the code continues, call an engineer.
Can a tenant reset an Ideal boiler?
Yes, using the reset button as described in the manual, and they can repressurise it. They must not open the casing or attempt gas repairs.
Template pack from Landlords Portal
Keep every gas safety, EICR and EPC date on track
The Property Inspection Kit includes an Excel tracker for gas safety, EICR and EPC dates, plus every document you need to inspect a property, written for landlords in England.
- Excel tracker for gas safety, EICR and EPC dates
- Room-by-room checklist, inspection report and photo log
- 24-hour notice letter, tenant repair report form and follow-up letters
