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2003 Lennox Industries Inc.
Litho U.S.A.
Corp. 0303−L2
G41UF
Service Literature
G41UF SERIES UNITS
G41UF series units are high−efficiency upflow gas fur
naces manufactured with Lennox DuralokPlus
t
alumi
nized primary and stainless steel secondary clamshelltype
heat exchangers. G41UF units are available in heating
input capacities of 44,000 to 132,000 Btuh (12.9 to 38.6 kW)
and cooling applications from 2 through 5 tons (7.0 through
17.6 kW). Refer to Engineering Handbook for proper sizing.
Units are factory equipped for use with natural gas. A kit is
available for conversion to LPG operation. All G41UF
units are equipped with the Lennox SureLight® hot sur
face ignition system. The gas valve is redundant to as
sure safety shut−off as required by C.S.A.
The heat exchanger, burners and manifold assembly can be
removed for inspection and service. The maintenance section
gives a detailed description on how this is done.
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are sub
ject to change. Procedures outlined in this manual are pre
sented as a recommendation only and do not supersede or
replace local or state codes.
Table of Contents
General
1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications
2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Blower Performance Data
3
. . . . . . . . . . . . . . . . . . . . . .
I−Unit Components
8
. . . . . . . . . . . . . . . . . . . . . . . . . . . .
II −Placement and Installation
16
. . . . . . . . . . . . . . . . . . .
III−Start−Up
21
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
IV−Heating System Service Checks
22
. . . . . . . . . . . . . .
V−Typical Operating Conditions
26
. . . . . . . . . . . . . . . . .
VI−Maintenance
27
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VII−Wiring and Sequence of Operation
30
. . . . . . . . . . .
VIII−Troubleshooting
35
. . . . . . . . . . . . . . . . . . . . . . . . . . .
CAUTION
As with any mechanical equipment, personal injury
can result from contact with sharp sheet metal
edges. Be careful when you handle this equipment.
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 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 discon
nect switch(es). Unit may have multiple
power supplies.