Stage #2 Boiler Pre-Heat A living area in the home is below the thermostat setting, resulting in an initial call for heat. The Digital Energy Manager interprets thermostat calls and begins pre-heating the boiler. With water circulating in the boiler, SYSTEM 2000 reaches operating temperature in less than ninety seconds. Website Credits ©1997-2004   Energy Kinetics, Inc. All rights reserved. For more information call 1-800-323-2066.