Is the Ideal Classic a good boiler?
It is a solid, plain boiler rather than a class leader. Ideal's own product fiche puts the Classic2 in seasonal space heating efficiency class A at 94%, with class A for water heating, in a casing only 700mm high, 395mm wide and 285mm deep. Every figure on this page is Ideal's published Classic2 data, in 24, 30 and 35kW. An older Classic can differ, so check the data plate. What you give up is the controls, the hot water headroom and, above all, the warranty.
What the Classic does well
- Efficiency is not the weak point. Class A on both heating and hot water, and Ideal quotes SEDBUK 2009 figures of 89% for the 24 and the 30, and 88.9% for the 35.
- It is genuinely compact. At 700 x 395 x 285mm and a maximum installation weight of about 30kg, it fits where bigger boilers do not.
- Noise is unremarkable. Ideal lists indoor sound power of 46dB on the 24 and the 30, and 41dB on the 35.
What to know before you buy one
- Central heating output is 24.2kW on all three models. The 30 and the 35 buy more hot water, not more heating power, so moving up the range does not solve a heat shortfall.
- The controls are basic. A mechanical 24 hour timer comes as standard, not a smart thermostat.
- Mains water pressure matters more than the badge. To reach its quoted flow rate the 24 needs at least 0.8 bar at the inlet, and the 30 and the 35 both need 1.3 bar.
- The warranty is the real catch. Ideal does not publish a warranty length for the Classic at all. Read the warranty section below.
- Ideal has moved on. The Classic is not on Ideal's combi boiler pages, which show the Logic and Vogue ranges, though Ideal still publishes the Classic2 manuals.
Who it suits: a one to three bedroom home with one bathroom, decent mains pressure and an owner who wants a straightforward gas combi. Who it does not: two showers at once, more than 24.2kW of heating, or anyone buying for a long warranty.
Which Ideal Classic size do I need?
There are three, and the number in the name is the hot water output, not the heating output. Every figure below comes from Ideal's own Classic2 installation and servicing manual.
| Model | Max. hot water output | Hot water flow rate (35°C rise) | Min. mains inlet pressure for that flow | Central heating output |
|---|---|---|---|---|
| Ideal Classic 24 | 24.2kW | 9.9 litres per minute | 0.8 bar | 4.8 to 24.2kW |
| Ideal Classic 30 | 30.3kW | 12.4 litres per minute | 1.3 bar | 6.1 to 24.2kW |
| Ideal Classic 35 | 35.3kW | 14.5 litres per minute | 1.3 bar | 7.1 to 24.2kW |
Ideal's own combi sizing guidance runs by radiator count: 24kW for up to 10 radiators, 28kW for 10 to 15, and 32kW for 15 to 20. Read those bands as hot water figures, because a Classic caps its heating at 24.2kW whichever one you fit.
None of this replaces a heat loss calculation, so let a Gas Safe registered engineer measure the property before anyone orders a boiler. If you are running out of hot water rather than heat, our guide to combi versus system boilers covers when a stored cylinder wins.
What does an Ideal Classic cost to buy and fit?
Ideal does not publish a price for the Classic, and no honest answer here is a single number. It sells through heating merchants, so what you are quoted is a fitted price built by your installer, not a list price you can look up.
What moves that quote is the work around the boiler: whether it stays put or the flue and pipework are re-run, whether the system gets a flush and an inhibitor dose, and which controls go in. Ask two or three installers for fully installed quotes on the same scope, and get the warranty term in writing.
How long is the warranty on an Ideal Classic?
Ideal does not publish one. Ideal's warranty length tables cover the Logic, Vogue, Mexico HE and Evomax 2 ranges and do not list the Classic. So get the term from your installer or merchant in writing before you buy, and do not assume it matches the Logic.
Whatever term you are given, Ideal's standard warranty terms and conditions decide whether you keep it. In Ideal's own words:
- "The warranty will commence from the date of installation. Without proof of purchase ie an invoice or completed 'Benchmark' commissioning sheet, the warranty will commence from the date of manufacture as detailed on the appliance data plate." Old merchant stock can therefore start its clock before it reaches your wall.
- "To qualify for the full warranty period the boiler must be registered within 30 days of installation." Miss that and the period "will extend to only 12 months from installation".
- "At the end of each 12 month period, the boiler must be serviced by a Gas Safe registered engineer. Should this condition not be met the boiler warranty will lapse."
- Ideal reserves the right to charge a call-out fee where a fault cannot be found, where the cause is excluded from the warranty, or where the boiler is outside the warranty period.
So: keep the invoice and the Benchmark sheet, register inside 30 days, and book the service every year. Our page on Ideal boiler warranties covers how a manufacturer warranty differs from a cover plan.
What goes wrong with an Ideal Classic?
The Classic shows a letter and a number on its display, and Ideal's manual lists what each means. Codes beginning L are lockouts, codes beginning F are faults.
| Code | What Ideal says it means |
|---|---|
| L1 | Flow temperature overheat lockout |
| L2 | Ignition lockout |
| LC | 5 resets within 15 minutes |
| L6 | False flame lockout |
| F1 | Low water pressure |
| F2, FN or LN | Flame loss |
| F3 | Fan fault |
| L4 or F4 | Flow thermistor fault |
| L5 or F5 | Return thermistor fault |
| F6 | Outside sensor fault |
| F7 | Low mains voltage |
| F8 or L8 | Lockout due to parameter fault |
| F9 or L9 | PCB fault |
The one that comes back every winter: L2
L2 is an ignition lockout, and on a condensing combi the common winter cause is a blocked or frozen condensate pipe rather than anything wrong with the boiler itself. Ideal describes the pattern in its user guide: the condensate backs up until the boiler "will make a gurgling noise prior to locking out an 'L2' fault code".
Ideal's published homeowner steps are to follow the plastic pipe outside, find the frozen section, and apply a hot water bottle, a microwaveable heat pack, a warm damp cloth or warm water from a watering can until it clears, then restart the boiler. Ideal is explicit about the limits: do not use boiling water, do not thaw pipework above ground level, and if you do not feel competent, call a Gas Safe registered engineer instead. More is on our Ideal L2 fault code page.
F1, and the pressure gauge
F1 is low water pressure. Ideal's fault finding for F1 asks for the gauge to read between 1 and 1.5 bar, while Ideal's user guide describes a typical original installation pressure of 1 to 2 bar and warns the boiler will not operate below 0.3 bar. Topping up once a year is normal. A system dropping every few weeks has a leak, and that needs an engineer, not another top-up. See what boiler pressure should be.
Restarting, and when to stop
The Classic2 is restarted by pressing the restart button on the control panel. An older Classic 24 or 30 is reset by turning the mode knob to the reset position and immediately turning it back to the setting you want. Do it once. If it locks out again, stop: five resets inside 15 minutes puts the boiler into LC, and restarting a boiler that keeps failing to light does not fix the cause. Ideal's guide says that if the boiler still fails to start, consult a Gas Safe registered engineer.
If you smell gas, or suspect a leak or carbon monoxide, leave the boiler alone and call the National Gas Emergency Service on 0800 111 999. Open the windows and doors, put out any naked flames, and do not operate electrical switches. Only a Gas Safe registered engineer may work on the appliance itself.
Repair it, or replace it?
If the fault is one component, repair is usually the better buy, and the efficiency argument for swapping is weaker than it sounds. On Ideal's own product fiche the Classic2 already sits in class A at 94%, so a current Ideal combi is not the leap an old non-condensing boiler would be.
The honest reasons to change are age, faults returning across different parts, a failed heat exchanger or gas valve, and parts getting harder to source now the range has left Ideal's main line-up. Get the diagnosis in writing first. Our guide on repairing versus replacing a boiler works through that decision.
Thinking about a repair on your Classic?
Smart Plan is a service plan, not insurance. Add the boiler and central heating module and you can request a repair, with parts and labour covered up to £500 in any 12 month period while the boiler is under seven years old, or up to £200 once it is older. Cover applies to the modules on your cover sheet, and to breakdowns that happen after your plan starts. A £95 call-out fee applies in the first 30 days and for anything the plan does not cover, and once you use the plan a 12 month agreement period begins. We aim to have an engineer with you within two working days, with call-outs booked Monday to Friday, 08:00 to 18:00, through a national network of thousands of Gas Safe registered engineers. Tell us what your boiler is doing and we will call you back.
Ideal Classic specifications
Ideal's published data for the Classic2. Outputs, flow rates and inlet pressures are in the sizes table above. Check the data plate before ordering parts.
| Classic 24 | Classic 30 | Classic 35 | |
|---|---|---|---|
| Height | 700mm | 700mm | 700mm |
| Width | 395mm | 395mm | 395mm |
| Depth | 285mm | 285mm | 285mm |
| Maximum installation weight | 29.9kg | 29.9kg | 30kg |
| Fuel | Natural gas (G20, 20mbar) | ||
| Boiler type | Condensing combination, cast aluminium heat exchanger | ||
| Seasonal space heating efficiency class | A (94% on Ideal's product fiche) | ||
| Water heating efficiency class | A | ||
| Seasonal efficiency (SEDBUK 2009) | 89% | 89% | 88.9% |
| Max. mains inlet pressure | 10 bar | ||
| Max. system working pressure | 2.5 bar | ||
| Sound power level, indoors | 46dB | 46dB | 41dB |
| NOx | 28 mg/kWh | 25 mg/kWh | 30 mg/kWh |
| NOx classification | Class 6 | ||
| Electrical supply | 230V ~ 50Hz, 3A external fuse | ||
| Flue terminal diameter | 100mm | ||
| Controls supplied | Mechanical 24 hour timer | ||
Ideal Classic questions homeowners ask
What is the correct pressure for an Ideal Classic?
Ideal's fault finding for the F1 low pressure code asks for the gauge to read between 1 and 1.5 bar, and Ideal's user guide describes a typical original installation pressure of 1 to 2 bar. It also states that the boiler will not operate below 0.3 bar. If pressure keeps dropping after you re-pressurise, get a Gas Safe registered engineer to find the leak.
How many showers can an Ideal Classic run at once?
Realistically one. The best of the three, the 35, delivers 14.5 litres a minute at a 35°C temperature rise, which is a good single shower. Split that across two outlets and both drop. If your home needs two hot outlets at once, a system boiler with a cylinder is the better answer.
Does an Ideal Classic need an annual service?
Yes, on two counts. Ideal's user guide says the appliance should be serviced at least once a year by a Gas Safe registered engineer, and Ideal's warranty terms say the warranty lapses if the boiler is not serviced at the end of each 12 month period. Keep the Benchmark service record filled in.
I let the property out. What do I have to do?
As a landlord you must have an annual gas safety check carried out by a Gas Safe registered engineer, under Regulation 36 of the Gas Safety (Installation and Use) Regulations 1998. The Health and Safety Executive states that you must "keep a record of the safety check for 2 years and issue a copy to each existing tenant within 28 days of the check being completed and issue a copy to any new tenants before they move in". The HSE landlord guidance has the full duty.
Can an Ideal Classic go in a garage or a loft?
Yes, if it is installed properly. Frost protection fires the boiler if the water inside falls below 5°C, in every mode, provided the power is left on. Ideal is clear that this protects the boiler and not the system, so pipework in an unheated space still needs lagging. For a loft boiler under warranty, Ideal also requires a fixed access ladder, lighting and fixed flooring.
Where can I find the official Ideal documents?
Ideal hosts the Classic2 installation guide and user guide on its own site, but they are not listed on the main Ideal Heating user guides index, so search for Classic2 by name or ask Ideal's technical helpline. The Ideal warranty terms and conditions are published separately.
