Furnace runs but radiators or air handlers do not get hot enough, long heat-up times

Safety first: Allow system to cool before bleeding radiators or opening any vents.

Steps:

• Check boiler settings: On the Intergas control panel, verify that the CH flow temperature is set appropriately for the system (e.g. 70–80°C for traditional radiators, lower for low-temperature systems).
• Bleed system: Bleed all radiators and high points to remove air. Re-pressurize the system as needed.
• Verify pump speed: If the pump has adjustable speed, set it according to system requirements. Too low a speed can cause poor circulation.
• Check filters: Clean any system filter or strainer on the return to the boiler.

If performance remains poor, a technician should check for sludge in the Intergas heat exchanger and consider power flushing the system.