Boiler runs but does not heat the house adequately; radiators or baseboards are lukewarm

Safety first: Turn off power before touching pumps or valves. Hot water can cause burns.

• Check system pressure: Ensure pressure is within the recommended range. Very low pressure can cause air pockets and poor circulation.
• Bleed air: Bleed radiators and high‑point vents until water flows steadily without air.
• Verify valve positions: Confirm all isolation and zone valves are fully open.
• Inspect circulator: During a call for heat, feel the circulator pump. It should be running and warm. If it is hot but not circulating, or cold and silent, it may need replacement.
• Clean strainers: If present, clean Y‑strainers or dirt separators to restore flow.