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UNIT INFORMATIONUNIT INFORMATION
Service Literature
©2016 Lennox Industries, Inc. 
 
 WARNING
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 licensed professional HVAC 
installer (or equivalent), service agency or the gas 
supplier.
 CAUTION
As with any mechanical equipment, contact with 
sharp sheet metal edges can result in personal 
injury. Take care while handling this equipment and 
wear gloves and protective clothing.
EL297UHV(X) series units are 90% eciency gas furnac-
es  used  for  upow  or  horizontal  applications  only,  man-
ufactured  with  Lennox  Duralok  heat  exchangers  formed 
of  aluminized steel.  EL297UHV(X)  units  are  available  in 
heating capacities of 44,000 to 132,000 Btuh and cooling 
applications up to 5 tons. Refer to Product Specications 
Manual for proper sizing.
Units are factory equipped for use  with natural gas. Kits 
are available for conversion to LPG operation. EL297UH-
V(X) model units are equipped with the icomfort
®
 enabled 
SureLight 
®
  two-stage  variable  speed  integrated  control. 
EL297UHV(X) unit meets the California Nitrogen Oxides 
(NOx)  Standards  and  California  Seasonal  Eciency  re-
quirements. All units use a redundant gas valve to assure 
safety shut-o as required by C.S.A.
All  specications  in  this  manual  are  subject  to  change. 
Procedures  outlined  in  this  manual  are  presented  as  a 
recommendation only and do not supersede or replace lo-
cal or state codes. In the absence of local or state codes, 
the guidelines and procedures outlined in this manual (ex-
cept where noted) are recommendations only and do not 
constitute code.
TABLE OF CONTENTS
Specications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2
Blower CFM Data  . . . . . . . . . . . . . . . . . . . . . . . . . Page 5
I Unit Components    . . . . . . . . . . . . . . . . . . . . . . . Page 26
II Installation    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 57
III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 79
IV Heating System Service Checks    . . . . . . . . . Page 80
V Typical Operating Characteristics    . . . . . . . . . Page 83
VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 83
VII Wiring and Sequence of Operation     . . . . . . Page 86
   Program Unit Capacity Size Mode     . . . . . . . Page 110
  Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . Page 111
EL297UHV(X)
100088
Communicating-ENABLED EL297UHV SERIES UNITS