How to Fix / Troubleshooting

Safety: Allow the system to cool before touching piping.

Check thermostat call: Ensure thermostats are set above room temperature and calling for heat.
Verify circulator operation: Feel the circulator pump(s) on the supply/return piping. They should vibrate slightly and get warm. If cold and silent, check power to the pump and its relay.
Inspect zone valves: Confirm manual levers on zone valves (if present) are not stuck in the closed position. Manually open one zone to test.
Bleed air: Use air vents on the Crown boiler and at high points in the system to remove trapped air that can block flow.
Check isolation valves: Make sure any service valves near the boiler are fully open.

Boiler runs but radiators or baseboards stay cold; no heat delivered to the home

Possible Causes