Room never reaches the set temperature; it stays several degrees below the setpoint even though the thermostat calls for heat.

Safety first: For any boiler adjustments, follow boiler manufacturer safety instructions or contact a heating professional.

Steps:

• Check other rooms: If all rooms are cold, the boiler flow temperature or system pressure may be too low; check boiler settings and pressure gauge.
• Bleed radiators: Use a radiator key to bleed trapped air from radiators, starting with the highest ones. Protect floors from water.
• Review floor temp limits: For underfloor heating, check the Ally thermostat’s maximum floor temperature setting and increase slightly if safe and within flooring manufacturer limits.
• Balance system: Ensure lockshield valves on radiators are not nearly closed, restricting flow. Adjust balancing if necessary.