3
2. Disconnect the connector harness from gas valve.
Disconnect wires from Hot Surface Igniter (HSI) and Flame
Sensor. Disconnect the two wires from the Low Gas
Pressure Switch (LGPS) located on the gas valve.
3. Support the manifold and remove the four (4) screws that
secure the manifold assembly to the burner box and set
aside.
4. Note the location of the green/yellow wire ground wire for
re
−
assembly later. See
.
5. Slide one
−
piece burner assembly out of slots on sides of
burner box.
6. Remove the flame sensor from the burner assembly. See
.
7. Remove the orifices from the manifold and discard.
Figure 2
Manifold Assembly
Orifice
Connect Green/Yellow
ground wire here
Manifold
Gas Valve
Gas valve must be installed on
manifold with minimum engagement of
6 threads. Cross threading is not
acceptable.
Indicated surfaces
to be 90 ˚+ or -2˚
CL
Gas valve is parallel to manifold
or - 3˚
A11407
Figure 3
Burner Assembly
FLAME SENSOR
(BELOW BURNER)
FLAME ROLLOUT
SWITCH
BRACKET, IGNITER
IGNITER
BURNER SUPT. ASSY
BURNER ASSY
A11403
ORIFICE SELECTION/DERATE
!
CAUTION
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit damage.
DO NOT re
−
drill burner orifices. Improper drilling may result in
burrs, out
−
of
−
round holes, etc. Obtain new orifices if orifice size
)
Figure 4
Burner Orifice
BURNER
ORIFICE
BURNER
ORIFICE
A96249
Determine natural gas orifice size and manifold pressure for
correct input at installed altitude by using
1. Obtain yearly heat
−
value average (at installed altitude) for
local gas supply.
2. Obtain yearly specific
−
gravity average for local gas supply.
3. Find installation altitude in
.
For Canada altitudes of 2000 to 4500 ft., use U.S.A. Altitudes of
2001 to 3000 ft. in
.
4. Find closest natural gas heat value and specific gravity in
.
5. Follow heat
−
value line and specific
−
gravity line to point of
intersection to find orifice size and manifold pressure
settings.
Furnace gas input rate on furnace rating plate is for installations
at altitudes up to 2000 ft. (610 M).
In the U.S.A
.; the input rating for altitudes above 2000 ft. (610 M)
must be reduced by 2 percent for each 1000 ft. (305 M) above
sea level.
In Canada
, the input rating must be derated by 5 percent for
altitudes of 2000 ft. to 4500 ft. (610 M to 1372 M) above sea
level.
The Conversion Kit Rating Plate accounts for high altitude
derate.
INSTALL ORIFICES
1. Install main burner orifices. DO NOT use Teflon tape.
Finger
−
tighten orifices at least one full turn to prevent
cross
−
threading, then tighten with wrench.
2. There are enough orifices in each kit for largest furnace.
Discard extra orifices.
DO NOT reinstall the manifold at this time.
REMOVE MIXER SCREWS FROM THE
BURNERS
Each burner contains a mixer screw that must be removed. Refer
1. Remove the mixer screws from the burners.
It is not necessary to plug the hole in the burner when the mixer
screws are removed.
Figure 5
Mixer Screw Location
A11501
1.9”
(48.76 mm)
1.8”
(46.96 mm)
Location of mixer screw
that must be removed
REINSTALL BURNER ASSEMBLY
To reinstall burner assembly:
1. Attach flame sensor to burner assembly.
2. Insert one-piece burner in slot on sides of burner box and
slide burner back in place.
3. Reattach HSI wires to HSI.
4. Verify igniter to burner alignment. See
&
.