BoilerFaultCodesThe 6 most common faults
Your smart thermostat display is blank because it has lost its wired connection to the heat pump or boiler interface, preventing you from controlling your heating.
Why it happens: This fault occurs when the physical data link between your smart thermostat's base and the heating appliance is broken or disconnected. The most common reason is a loose wire or a poor connection at the terminals, which prevents the screen from receiving the power and digital information it needs to function.
Full guide for No illumination (HP Comms)Your smart thermostat is unable to talk to your boiler because the wired connection between them has been lost or disconnected.
Why it happens: This fault occurs when the physical data link between the boiler's internal computer and the smart interface is broken or interrupted. It is usually caused by a loose connection at the wiring harness or a component failure that stops the two parts from sharing information. Without this constant stream of data, the boiler cannot receive commands from your thermostat to turn the heating on.
Full guide for HP Comms No illuminationYour smart thermostat has lost its wireless connection to the boiler, meaning you cannot control your heating remotely or via the wall unit.
Why it happens: This fault occurs when the radio frequency link between your thermostat and the smart interface plugged into the boiler is interrupted. The most common reasons are physical obstructions like new furniture or thick walls blocking the signal, or electronic interference from other household devices.
Check that your home Wi-Fi router is switched on and working correctly.Ensure the Halo Smart Interface (the white box plugged into the boiler) has power and is not obstructed.Navigate to the 'Settings' menu on the Halo unit and select 'Pairing Mode' to reconnect the device to the interface.
Your thermostat has lost its wireless connection to the boiler, meaning your heating controls cannot talk to the system.
Why it happens: This fault occurs when the wireless signal between your thermostat and the smart interface plugged into the boiler is interrupted or lost. The most common reasons include simple dead batteries in the wall unit, physical obstructions like new furniture blocking the signal, or radio interference from other electronic devices in your home.
Check that the internet router is switched on and functioning correctly.Ensure the Smart Interface plugged into the boiler is powered and has a light showing.Restart the Halo thermostat by removing and reinserting the batteries.Navigate to the advanced settings on the thermostat to re-pair the device to the interface.
Your smart thermostat has lost connection with the boiler, causing it to enter a backup safety mode to ensure you aren't left without heat.
Why it happens: This fault occurs when the wireless connection between your thermostat and the boiler's interface is interrupted or lost. The most common reasons are dead batteries in the wall unit, electronic interference from other household devices, or the thermostat being moved too far away from the boiler.
Check if the Halo thermostat batteries need replacing.Ensure the Halo thermostat is within range of the boiler and has not been moved behind a metal object.Restart your internet router if the problem persists.Press and hold the override button on the boiler interface for 3 seconds to attempt a manual reconnect.
Your heating system is currently trying to establish a link between the heat pump and its control unit.
Why it happens: This code appears when the main heat pump unit is trying to find and sync with the smart control interface inside your home. It usually happens during the initial setup or immediately after a power cut as the components reboot and exchange data. In most cases, it is simply a startup sequence rather than a hardware failure.
Wait up to 10 minutes for the setup to finish automaticallyEnsure the Smart Interface is powered onIf it persists beyond 15 minutes, press the reset button on the interface
on the Ideal Halo Air RF WI FI 2 Zone
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Ideal shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue