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AVERTISSEMENT
RISQUE D'EXPLOSION ET D'INCENDIE
Le fait de ne pas suivre cet avertissement pourrait entraîner des
dommages corporels et / ou la mort.
Ne jamais examiner pour les fuites de gaz avec une flamme
vive. Utilisez plutôt un savon fait specifiquement pour la
détection des fuites de gaz pour verifier tous les connections.
Un incendie ou une explosion peut entrainer des dommages
matériels, des blessures ou la mort.
1. Be sure main gas and electric supplies to furnace are off.
2. Remove 1/8-in. NPT pipe plug from manifold pressure tap
on downstream side of gas valve.
3. Attach manometer to manifold pressure tap on gas valve.
(see Fig. 13.)
4. Turn gas supply manual shutoff valve to ON position.
5. Turn furnace gas valve switch to ON position.
6. Check all threaded pipe connections for gas leaks.
7. Turn on furnace power supply.
MODULATING
ON/OFF Switch
Inlet
Pressure Tap
Fig. 13 - - Gas Valve
GAS INPUT RATE INFORMATION
See furnace rating plate on blower door for input rate. The input
rate for natural gas is determined by manifold pressure and orifice
size.
The gas valve must be set for Maximum Heat first and then set
for Minimum Heat on Modulating furnaces.
Determine natural gas orifice size and manifold pressures for
correct input at installed altitude by using Table 3 (for 20,000
Btuh/Max- -Heat/8000 Btuh Min- -Heat per Burner) or Table 4
(For 20,200 Btuh Max Heat/8,000 Btuh Min- -Heat per Burner).
1. Obtain yearly heat- -value average (at installed altitude) for
local gas supply.
2. Obtain yearly specific- -gravity average for local gas sup-
ply.
3. Find installation altitude in Table 3 or Table 4, depending
on furnace gas input rate.
NOTE: For Canada altitudes of 2000 to 4500 ft. (610 to 1372
M), use U.S.A. Altitudes of 2001 to 3000 ft. (610 to 914 M) in
Table 3 or Table 4, depending on furnace gas input rate.
4. Find closest natural gas heat value and specific gravity in
Table 3 or Table 4, depending on furnace gas input rate.
Min/Max Heat Adust
(Under Cap)
Turn screw 1 click per
second to adjust rate.
Clockwise to increase
rate, counter clockwise
to decrease rate.
1/2" NPT Outlet
Manifold
Pressure Tap
A11513
5. Follow heat- -value line and specific- -gravity line to point
of intersection to find orifice size and maximum and min-
imum manifold pressure settings.
Furnace gas input rate on 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. (610M)
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. (610 M) to 4500 ft. (1372 M) above sea
level.
The Conversion Kit Rating Plate accounts for high altitude
derate.
SET GAS INPUT RATE
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in gas valve
damage.
DO NOT force the rotary adjustment switch on the
modulating gas valve. DO NOT turn the rotary adjustment
switch faster than one click per second when adjusting
manifold pressure. Gas valve will be damaged if excessive
force is used on the rotary switch.
Burner Flame
Manifold
Fig. 14 - - Burner Flame
For proper operation and long term reliability, the manifold
pressure must be adjusted as specified on the conversion kit rating
plate.
The modulating furnace manifold pressure is set at two points.
The first point is Maximum Heat. The second point is Minimum
Heat. DO NOT adjust Intermediate Heat manifold pressure.
Intermediate Heat manifold pressure can be checked as part of the
temperature rise, but is not adjustable. Always adjust Maximum
Heat first, then Minimum Heat.
NOTE:
Use care when performing adjustments. Gas valve
adjustment is performed by turning a rotary adjustment switch
inside the gas valve with a small straight blade screwdriver.
Excessive force can break or bend the rotary adjustment switch
making it non- -adjustable.
To adjust manifold pressure to obtain input rate for Maximum
Heat:
1. Make sure the gas supply is turned off to the furnace and
at the electric switch on the gas valve.
2. Remove the 1/8 inch NPT plug from the outlet pressure
tap on the gas valve.
3. Connect a manometer to the outlet pressure tap on gas
valve.
4. Turn on furnace power supply.
5. Turn gas supply manual shutoff valve to ON position.
11
Burner
A11461
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