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© 2008 Lennox Industries Inc.
Corp. 0804−L2
G71MPP
Service Literature
Revised 05−05−2008
G71MPP SERIES UNITS
G71MPP series units are high−efficiency multi−position
(upflow, downflow, horizontal right and left) gas furnaces
equipped with variable capacity gas valve, variable speed
combustion air inducer and variable speed indoor blower
motor. All models are designed only for direct vent (dual
pipe) venting system. G71MPP units are available in heat-
ing capacities from 66,000 to 132,000 Btuh (19.3 to 38.6
kW) and cooling applications from 2 to 5 tons (7.0 kW to
17.5 kW). Refer to Engineering Handbook for proper siz-
ing.
Units are factory equipped for use with natural gas. Kits are
available for conversion to LPG operation. G71MPP model
units are equipped with the Lennox SureLight
®
variable ca-
pacity integrated control. All G71MPP units meet the Califor-
nia Nitrogen Oxides (NO
x
) Standards and California Sea-
sonal Efficiency requirements.
All specifications in this manual are subject to change. Pro-
cedures outlined in this manual are presented as a recom-
mendation 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 recommendations only and do not consti-
tute code.
TABLE OF CONTENTS
Specifications Page 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Optional Accessories Page 3. . . . . . . . . . . . . . . . . . . . . .
Blower Data Page 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
I Unit Components Page 16. . . . . . . . . . . . . . . . . . . . . . .
Control Box 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Compartment 28. . . . . . . . . . . . . . . . . . . . . . . . .
Heating Components 30. . . . . . . . . . . . . . . . . . . . . . . . .
II Installation Page 36. . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Start Up Page 47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV Heating System Service Checks Page 48. . . . . . . . .
V Typical Operating Characteristics Page 51. . . . . . . . .
VI Maintenance Page 52. . . . . . . . . . . . . . . . . . . . . . . . . .
VII Wiring and Sequence of Operation Page 54. . . . . .
VIII Field Wiring Page 61. . . . . . . . . . . . . . . . . . . . . . . . .
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a licensed professional installer (or
equivalent), 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 discon-
nect 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.
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