Ideal Boilers isar HE24

Questions and Answers

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Theresa MoralesAug 1, 2025
How to fix Ideal Boilers Boiler that will not fire for central heating?
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  nicole98Aug 1, 2025
  If your Ideal Boilers boiler isn't working for central heating, ensure your external programmer is set to an ‘ON’ period. If it is already set to ‘ON’, set the programmer to continuous. If the boiler then fires, contact your installer to fix the programmer. Also, check the room thermostat by turning it up fully. If ‘0’ is not displayed on the user controls, contact your installer.
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Kevin HunterAug 5, 2025
What to do if Ideal Boilers Boiler is not working and display shows ‘LLLLL ::::: FFFFF ’?
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  Dominique Willis MDAug 5, 2025
  If your Ideal Boilers boiler displays ‘LLLLL ::::: FFFFF ’ (flashing) and isn't working for central heating or hot water, but attempts to fire, press the reset button (D) for 2 seconds to try the ignition sequence again. Also, check your gas supply by testing another appliance. If there's no gas, contact your gas supplier, as it's not a boiler fault. Finally, inspect the condensate pipe for blockages or freezing. If blocked, clear it; if you can't, contact your installer.
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Grace EvansAug 10, 2025
What to do if Ideal Boilers Boiler displays ‘HHHHH:::::AAAAA ’?
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  Pamela SalinasAug 10, 2025
  If your Ideal Boilers boiler is not working for central heating or hot water and the display shows ‘HHHHH:::::AAAAA ’ (flashing), first check that the pressure gauge on the boiler shows at least 1 bar. If it's lower, re-pressurize it to 1 bar using the filling loop. If you're unsure how to do this, contact your installer. After re-pressurizing, turn off the tap on the filling loop, then turn the boiler off and back on again to reset it. If the pressure continues to drop, contact your installer. Also, check if all radiators have thermostatic radiator valves; if they do, contact your installer.
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David AcostaAug 15, 2025
What to do if Ideal Boilers isar HE24 display shows ‘LLLLL:::::AAAAA ’?
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  Karen CarlsonAug 15, 2025
  If your Ideal Boilers boiler is not working and the display shows ‘LLLLL:::::AAAAA ’ (flashing), this indicates an overheat condition. Press the reset button (D) for 2 seconds to try re-lighting the boiler. If the fault happens again, turn off the boiler and contact your installer. Also, check if all radiators have thermostatic radiator valves fitted; if they do, contact your installer.
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Sara CamposAug 20, 2025
What to do if Ideal Boilers Boiler comes on for hot water without tap being opened?
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  Frank HoganAug 20, 2025
  If your Ideal Boilers boiler comes on for domestic hot water without a tap being opened and the display shows ‘D’, check for dripping or dribbling taps or showers and ensure they are fully turned off. Also, check for leaks from the domestic hot water pipework, and if you find any, contact your installer.
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biancataylorAug 26, 2025
Why Ideal Boilers isar HE24 Boiler fires occasionally for approx. 2 minutes?
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  James Crawford IIAug 26, 2025
  This is a normal function of the Ideal Boilers boiler. It periodically pre-heats the plate heat exchanger to optimize the delivery time for domestic hot water to taps or showers.

Summary

Introduction to the Isar Boiler

Boiler Description

Wall-mounted, room-sealed, condensing combination boiler with automatic spark ignition and fan-assisted combustion.

Condensate and Flue Gases

High efficiency produces condensate drained via plastic waste pipe; a condensate plume may be visible at the flue terminal.

Dual Functionality

Provides both central heating and instantaneous domestic hot water.

Safety and Installation Requirements

Gas Safety Regulations

Mandatory installation by a CORGI registered installer in accordance with current regulations.

Electrical Safety

Appliance must be earthed; 230V~50Hz supply with 3A fusing; requires double-pole switch isolation.

Operational Safety Notes

Ensure casing is fitted, avoid storage in compartments, do not use with faults, and do not tamper with sealed components.

Boiler Operation and Controls

Minimum Installation Clearances

Required clearances: 165mm above, 100mm below, 5mm sides, 450mm front for servicing.

Boiler Lighting Procedure

Step-by-step guide to lighting the boiler, including checking power, setting controls, and switching on.

Normal Operation Indicators

Understanding display codes for standby, CH supply, DHW supply, and DHW preheat status.

Winter Operating Mode

Boiler fires for CH and DHW, prioritizing DHW demand. DHW preheat functions during periods without CH demand.

Advanced Operation and Troubleshooting

Summer Operating Mode

Boiler fires periodically to maintain DHW calorifier preheated condition, with pump operating hourly for self-check.

Water Temperature Control

Adjusting DHW temperature via thermostat knob (max 65°C) and CH temperature (max 82°C).

Boiler Shutdown and Restart

Procedure for short and long periods, including draining the system for extended shutdowns.

Frost Protection Measures

Recommendations for preventing frost damage during short absences or when using a frost thermostat.

Boiler Safety Shutdowns

Overheat thermostat (LA fault) and flame failure (LF fault) procedures, requiring reset or installer intervention.

System Pressure and Condensate

Monitoring system pressure, handling low pressure, and ensuring the condensate drain is clear and unobstructed.

Escape of Gas Protocol

Immediate action for suspected gas leaks: contact local gas supplier; do not use naked flames.

Cleaning and Maintenance

Instructions for cleaning with dry/damp cloths and annual servicing by a qualified installer.

Troubleshooting Common Non-Product Faults

Boiler Not Working (No Ignition)

Check power supply, gas, and condensate blockage. Attempt reset for ignition sequence failure.

Boiler Not Working (Overheat;Flame Fault)

Addresses 'LA' (overheat) and 'LF' (flame failure) faults, requiring reset or installer contact.

Boiler Not Working (System Pressure;TRVs)

Check system pressure (min 1 bar) and thermostatic radiator valves (TRVs) affecting operation.

Boiler Not Firing for Central Heating

Verify programmer 'ON' period, room thermostat setting, and contact installer if issues persist.

Unintended Domestic Hot Water Operation

Checks for dripping taps/showers or leaks in domestic hot water pipework causing unintended firing.

Periodic Boiler Firing (Display t)

Normal function for pre-heating the heat exchanger to optimize DHW delivery time.

Seasonal DHW Temperature Variation

Explains how ambient cold main water temperature affects DHW flow rate and temperature.