G40UH(X) - Lennox Hvac Manuals (2024)

Service Literature Corp. 0006−L3 Revised 09−2006 <strong>G40UH</strong>(X) <strong>G40UH</strong>(X) series units are mid−efficiency gas furnaces used for upflow or horizontal applications only, manufactured with <strong>Lennox</strong> Duralok Plus heat exchangers formed of aluminized steel. <strong>G40UH</strong>(X) units are available in heating capacities of 44,000 to 154,000 Btuh and cooling applications up to 5 tons. Refer to Engineering Handbook for proper sizing. Units are factory equipped for use with natural gas. Kits are available for conversion to LPG operation. <strong>G40UH</strong>(X) model units are equipped with a hot surface ignition system. The <strong>G40UH</strong>(X) unit meets the California Nitrogen Oxides (NO x ) Standards and California Seasonal Efficiency requirements. All units use a redundant gas valve to assure safety shut−off as required by C.S.A. All specifications in this manual are subject to change. Procedures outlined in this manual are presented as a recommendation only and do not supersede or replace local or state codes. In the absence of local or state codes, the guidelines and procedures outlined in this manual (except where noted) are recommended only and do not constitute code. TABLE OF CONTENTS Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2 Blower Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4 High Altitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 13 Parts Identification . . . . . . . . . . . . . . . . . . . . . . . . Page 14 I Unit Components . . . . . . . . . . . . . . . . . . . . . . . Page 16 II Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 24 III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 24 IV Heating System Service Checks . . . . . . . . . Page 24 V Typical Operating Characteristics . . . . . . . . . Page 28 VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 28 VII Wiring and Sequence of Operation . . . . . . Page 30 VIII SureLight Troubleshooting Guide . . . . . . . Page 41 IMPORTANT Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a qualified installer, service agency or the gas supplier. WARNING Electric shock hazard. Can cause injury or death. Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at disconnect switch(es). Unit may have multiple power supplies. WARNING Sharp edges. Be careful when servicing unit to avoid sharp edges which may result in personal injury. Page 1 © 2000 <strong>Lennox</strong> Industries Inc.