Display shows HIGH LIMIT or boiler shuts down at high temperature; burner cycles off before zones are heated.

Safety: Hot water and steam can cause severe burns. Allow the boiler to cool and shut off power before touching piping or controls.

• 1. Check system circulators: On Energy Kinetics System 2000, verify that the system circulator and zone circulators run when there is a call for heat. Listen for pump operation and feel for vibration. If a circulator is silent and cool, check its power supply and fuses.
• 2. Bleed air from zones: Air in the system can stop flow and cause rapid temperature rise. Use zone purge valves or bleeders to remove air, following the boiler manual.
• 3. Inspect high limit setting: Confirm the high limit aquastat or control is set to the recommended temperature (often around 180–200°F). Do not raise the limit above manufacturer specifications.
• 4. Check plate heat exchanger: If domestic hot water is slow and boiler temperature spikes, the plate heat exchanger may be restricted. This requires professional cleaning or replacement.