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VI-MAINTENANCE
Annual Furnace Maintenance
At the beginning of each heating season, and to comply 
with the Lennox Limited Warranty, your system should be 
checked by a licensed professional technician (or equiva-
lent) as follows:
 WARNING
Disconnect power before servicing unit.
 CAUTION
Label all wires prior to disconnection when servicing 
controls. Wiring errors can cause improper and 
dangerous operation. Verify proper operation after 
servicing.
 WARNING
Electric Shock Hazard. Can cause injury or death. 
Unit must be properly grounded in accordance with 
national and local codes.
 WARNING
Fire Hazard. Use of aluminum wire with this product 
may  result  in  a  re,  causing  property  damage, 
severe injury or death. Use copper wire only with 
this product.
 IMPORTANT
If a high eciency lter is being installed as part of 
this system to ensure better indoor air quality, the 
lter must be properly sized. High eciency lters 
have a higher static pressure drop than standard 
eciency glass/foam lters. If the pressure drop is 
too great, system capacity and performance may be 
reduced.
The pressure drop may also cause the limit to trip 
more frequently during the winter and the indoor 
coil to freeze in the summer, resulting in an increase 
in the number of service calls.
Before using  any  lter  with  this system, check the 
specications  provided  by  the  lter  manufacturer 
against the data given in the appropriate Lennox 
Product  Specications  bulletin.  Additional 
information is provided in Service and Application 
Note ACC002 (August 2000).
 WARNING
The inner blower access panel and vent pipe must be 
securely in place when the blower and burners are 
operating. Gas fumes, which could contain carbon 
monoxide, can be drawn into living space resulting 
in personal injury or death.
1-  Check  wiring  for  loose  connections,  voltage  at  indoor 
unit and amperage of indoor motor.
2-  Check  the  condition  of  the  belt  and  shaft  bearings  if 
applicable.
3-  Inspect all gas pipe and connections for leaks.
4-  Check the cleanliness of lters and change if necessary 
(monthly).
5- Check the condition and cleanliness of burners and heat 
exchanger and clean if necessary. 
6-  Check  the  cleanliness  of  blower  assembly  and  clean 
the housing, blower wheel and blower motor if neces-
sary . The blower motors are prelubricated for extended 
bearing life. No further lubrication is needed.
7-  Inspect the combustion air inducer and clean if neces-
sary.
8-  Evaluate the heat exchanger integrity by inspecting the 
heat exchanger per the AHRI heat exchanger inspec-
tion procedure. This procedure can be viewed at www.
ahrinet.org
9-  Ensure sucient combustion air is available to the fur-
nace. Fresh air grilles  and louvers (on the unit and in 
the  room where the furnace is installed) must be prop-
erly sized, open and unobstructed to provide combus-
tion air.
10-  Inspect the furnace venting system to make sure it is 
in  place, structurally sound, and without holes, corro-
sion, or blockage. Vent system must be free and clear 
of obstructions and must slope upward away from the 
furnace . Vent system should be installed per the Na-
tional Fuel Gas Code
11-  Inspect the furnace return air  duct  connection  to  en-
sure the  duct  is sealed  to  the  furnace. Check  for  air 
leaks on supply and return ducts and seal where nec-
essary.
12-  Check the condition of the furnace cabinet insulation 
and repair if necessary.
13-  Perform  a  complete  combustion  analysis  during  the 
furnace inspection  to  ensure  proper  combustion and 
operation. Consult Service Literature for proper com-
bustion values.
14-  Verify operation of CO detectors and replace batteries 
as required.
Perform  a  general  system  test.  Turn  on  the  furnace  to 
check operating functions such as the start-up and shut-of 
operation.
1 -  Check the operation of the ignition system, inspect and 
clean ame sensor. Check microamps before and after. 
Check  controls  and  safety  devices  (gas  valve,  ame 
sensor,  temperature  limits).  Consult  Service  Manual 
for proper operating range. Thermal Limits should be 
checked  by  restricting  airow  and  not  disconnecting 
the  indoor  blower.  For  additional  details,  please  see 
Service and Application Note H049.