Inventors:
William Brian Griffin - Columbia PA, US
Brandon Charles Wellington - Philadelphia PA, US
Assignee:
Captive-Aire Systems, Inc. - Raleigh NC
International Classification:
F24D 5/02, F23N 5/00, F24D 19/10
Abstract:
A heated air makeup unit comprising a heating chamber with a modulated furnace one or more non-modulated furnaces air temperature control and efficient furnace operation over a wide heating rate range. The utilization of indirect fired furnaces in the heated air makeup unit is disclosed. A control system is included to provide control of heated air temperature to within +/−1 F.° using continuous control of the heating rate of the modulated furnace and stepwise activation and de-activation of the non-modulated furnaces in response to heating demand. A programmed combustion air flow controller programmed to provide optimal airflow for any gas flow in a flow range of a modulating gas valve is provided to assure combustion efficiencies of at least %.