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15 -  Disconnect the condensate drain line.
16 -  Remove cold end header box.
17 -  Remove electrical junction box from the side of the 
furnace.
18 -  Mark  and  disconnect  any  remaining  wiring  to 
heating  compartment  components.  Disengage 
strain  relief  bushing  and  pull  wiring  and  bushing 
through the hole in the blower deck.
19 -  Remove the primary limit from the vestibule panel.
20 -  Remove  two  screws  from  the  front  cabinet  ange 
at the blower deck. Spread cabinet sides slightly to 
allowclearance for removal of heat exchanger.
21 -  Remove screws along  vestibule  sides and  bottom 
which secure  vestibule  panel  and  heat  exchanger 
assembly  to  cabinet.  Remove  two  screws  from 
blower  rail  which  secure  bottom  heat  exchanger 
ange.  Remove  heat  exchanger  from  furnace 
cabinet.
22 -  Back  wash  heat  exchanger  with  soapy  water 
solution or steam. If steam is used it must be below 
275°F (135°C) .
23 -  Thoroughly  rinse  and  drain  the  heat  exchanger. 
Soap solutions can be corrosive. Take care to rinse 
entire assembly.
24 -  Reinstall heat exchanger into cabinet making sure 
that the clamshells of the heat exchanger assembly 
is engaged properly into the support bracket on the 
blower deck. Remove the indoor blower to view this 
area through the blower opening.
25 -  Re-secure the supporting screws along the vestibule 
sides and bottom to the cabinet.
26 -  Reinstall  cabinet  screws  on  front  ange  at  blower 
deck.
27 -  Reinstall the primary limit on the vestibule panel.
28 -  Route  heating  component  wiring  through  hole  in 
blower deck and reinsert strain relief bushing.
29 - Reinstall electrical junction box.
30 - Reinstall the cold end header box.
31 -  Reinstall the combustion air inducer. Reconnect the 
plug to the wire harness.
32 -  Reinstall pressure switches and reconnect pressure 
switch wiring.
33 -  Carefully  connect  combustion  air  pressure  switch 
tubing  from  pressure  switches  to  proper  ports  on 
cold end header collector box.
34 -  Reconnect  condensate  drain  line  to  the  cold  end 
header box.
35 -  Use securing screws to reinstall ue collar to the top 
cap on the furnace. Reconnect exhaust piping and 
exhaust drain tubing.
36 -  Replace exible exhaust adapter on combustion air 
inducer  and  ue  collar.  Secure  using  two  existing 
hose clamps.
37 -  Reinstall  burner  box  assembly  in  vestibule  area. 
Secure  burner  box  assembly  to  vestibule  panel 
using four existing screws. Make sure burners line 
up in center of burner ports.
38 -  Reconnect ame roll-out switch wires.
39 -  Reconnect  sensor  wire  and  reconnect  2-pin  plug 
from ignitor.
40 -  Reinstall gas valve manifold assembly. Reconnect 
gas supply line to gas valve.
41 -  Reconnect the combustion air intake pipe.
42 -  Reinstall burner box cover.
43 -  Reconnect wires to gas valve.
44 -  Replace the blower compartment access panel.
45 -  Reconnect  gas  supply  piping. Turn on  power  and 
gas supply to unit.
46 -  Follow  lighting  instructions  on  unit  nameplate  to 
light  and  operate  furnace  for  5  minutes  to  ensure 
the furnace is operating properly.
47 -  Check all piping connections, factory and eld, for 
gas  leaks.  Use  a  leak  detecting  solution  or  other 
preferred means.
48 -  Replace heating compartment access panel.
 CAUTION
Some soaps used for leak detection are corrosive to certain 
metals. Carefully rinse piping thoroughly after leak test has been 
completed. Do not use matches, candles, ame or other sources 
of ignition to check for gas leaks.
Cleaning the Burner Assembly (if needed)
1 -   Turn o electrical and gas power supplies to furnace. 
Remove upper and lower furnace access panels.
2 -   Disconnect the wires from the gas valve.
3 -   Remove the burner box cover (if equipped).
4 -   Disconnect the gas supply line from the gas valve. 
Remove gas valve/manifold assembly.
5 -   Mark and disconnect sensor wire from the sensor. 
Disconnect wires from ame rollout switches.
6 -   Disconnect  combustion  air  intake  pipe.  It  may  be 
necessary to cut the existing pipe to remove burner 
box assembly.
7 -   Remove  four  screws  which  secure  burner  box 
assembly to  vest  panel.  Remove  burner  box  from 
the unit.
8 -   Use the soft brush attachment on a vacuum cleaner 
to  gently  clean  the  face  of  the  burners.  Visually 
inspect the inside of the burners and crossovers for 
any  blockage  caused  by  foreign  matter.  Remove 
any blockage.
9 -   Reinstall the burner box assembly using the existing 
four screws. Make sure that the burners line up in 
the enter of the burner ports.
10 -  Reconnect the sensor wire and reconnect the 2-pin 
plug to the ignitor wiring harness. Reconnect wires 
to ame rollout switches.
11 -  Reinstall  the  gas  valve  manifold  assembly. 
Reconnect  the  gas  supply  line  to  the  gas  valve. 
Reinstall the burner box cover.
12 - Reconnect wires to gas valve.
13 - Replace the blower compartment access panel.
14 -  Refer to  instruction on  verifying gas  and electrical 
connections when re-establishing supplies.
15 -  Follow  lighting  instructions  to  light  and  operate 
furnace for 5 minutes to ensure that heat exchanger 
is  clean  and  dry  and  that  furnace  is  operating 
properly.
16 - Replace heating compartment access panel.