Boiler runs but house does not heat, radiators or baseboards stay cool

Safety: Turn off power before touching the circulator or electrical connections. Hot water can cause burns.

Steps:

• 1. Feel supply and return pipes: If the boiler is hot but the supply piping leaving the boiler is only warm near the boiler and cold further out, circulation is suspect.
• 2. Check circulator operation: With a call for heat, carefully touch the circulator body. It should vibrate slightly and get warm. If cold and silent, the pump may not be running.
• 3. Verify valves: Ensure all isolation valves around the circulator and on main loops are open.
• 4. Bleed air: Use purge valves or manual bleeders to remove air from the system. Air can prevent flow even if the pump runs.

Professional repair: If the circulator is powered but not moving water, it likely needs replacement. A technician should also verify correct pump sizing and wiring.