Adjustments - Bryant 311AAV Series 100 Installation, Start-Up, And Operating Instructions Manual

TABLE 7—MODEL 311AAV ORIFICE SIZE* AND MANIFOLD PRESSURE FOR GAS INPUT RATE (CONTINUED)
(TABULATED DATA BASED ON 22,000 BTUH PER BURNER, DERATED 4 PERCENT FOR EACH 1000 FT ABOVE SEA LEVEL)
AVG GAS
ALTITUDE
HEAT VALUE
RANGE
AT ALTITUDE
(FT)
(BTU/CU FT)
575
600
625
650
9001
to 675
10,000
700
725
750
775
* Orifice numbers (43) shown in shading are factory installed.
WARNING: Never purge a line into a combustion
chamber. Never use matches, candles, flame, or other
sources of ignition for the purpose of checking leakage.
Use a soap-and-water solution to check for leakage.
Failure to follow this warning can cause fire, explosion,
personal injury, or death.
2. Component Self-Test:The furnace control allows all com-
ponents, except the gas valve, to be run for short period of
time. This feature helps diagnose a system problem in case
of a component failure. To begin component test procedure,
short (jumper) the C
OM
TEST/TWIN 3/16-inch quick-connect terminal on control
(behind the Y/Y2 terminal) for approximately 2 sec. (See
Fig. 22.)
NOTE: Component test feature will not operate if any thermostat
signal is present at the control.
Component test sequence is as follows:
a. Momentarily short (jumper) TEST/TWIN and C
terminals until LED goes off.
b. LED will display previous status code 4 times.
c. Inducer motor starts and continues to run for entire
component test sequence.
d. Hot surface igniter is energized for 15 sec., then de-
energized.
e. Blower motor operates on FAN speed for 10 sec.
f. Blower motor operates on HEAT speed for 10 sec.
g. Blower motor operates on COOL speed for 10 sec.
h. Inducer motor stops.
3. Operate Furnace: Follow procedures on operating instruc-
tions label attached to furnace.
4. Furnace Restart: With the furnace operating, set the
thermostat below room temperature and observe that the
furnace goes off. Set the thermostat above room tempera-
ture and observe that the furnace restarts.
IV. ADJUSTMENTS
1. Set gas input rate
Furnace gas input rate on rating plate is for installations at
altitudes up to 2000 ft. Furnace input rate must be within ±2
percent of furnace rating plate input.
In the U.S.A., the input rating for altitudes above 2,000 ft.
must be reduced by 4
for each 1,000 ft. above sea level.
In Canada, input rating must be reduced by 10
0.58
Orifice Manifold Orifice
No. Pressure No.
43 2.7 43
43 2.5 43
43 2.3 43
43 2.1 43
48 3.7 43
48 3.4 48
49 3.8 48
49 3.5 49
49 3.3 49
-24v terminal on control and the
OM
SPECIFIC GRAVITY OF NATURAL GAS
0.60 0.62
Manifold Orifice Manifold
Pressure No. Pressure
2.8 43
2.6 43
2.4 43
2.2 43
2.0 43
3.6 48
3.3 48
3.6 49
3.4 49
for altitudes of 2,000 ft. to 4,500 ft. above sea level.
4. Determine natural gas orifice size and manifold pressure for
correct input.
a. Obtain average yearly gas heat value (at installed alti-
tude) from local gas supplier.
b. Obtain average yearly gas specific gravity from local gas
supplier.
c. Verify furnace model. Table 7 can only be used for
model 311AAV furnaces.
NOTE: For Canada altitudes of 2000 to 4500 ft, use U.S.A.
altitudes of 2001 to 3000 ft in Table 7.
d. Find installation altitude in Table 7.
e. Find closest natural gas heat value and specific gravity in
Table 7.
f. Follow heat value and specific gravity lines to point of
intersection to find orifice size and manifold pressure
-24v
setting for proper operation .
g. Check and verify burner orifice size in furnace. NEVER
ASSUME ORIFICE SIZE. ALWAYS CHECK AND
VERIFY.
EXAMPLE: (0–2000 ft altitude)
Heating value = 975 Btu/cu ft
Specific gravity = 0.62
Therefore: Orifice No. 43*
Manifold pressure 3.6-in. wc
* Furnace is shipped with No. 43 orifices. In this example
all main burner orifices are the correct size and do not need
to be changed to obtain proper input rate.
5. Adjust manifold pressure to obtain input rate.
a. Remove regulator adjustment-screw seal cap. (See Fig.
31)
b. Jumper R and W thermostat terminals on control to start
furnace.
c. Turn adjusting screw, counterclockwise (out) to decrease
input rate or clockwise (in) to increase input rate.
NOTE: This furnace has been approved for a manifold pressure
of 3.2-in. wc to 3.8-in. wc when installed at altitudes up to 2000 ft.
For altitudes above 2000 ft, the manifold pressure can be adjusted
from 2.0-in. wc to 3.8-in. wc.
—21—
0.64
Orifice Manifold
No. Pressure
2.9 43 3.0
2.7 43 2.7
2.4 43 2.5
2.3 43 2.3
2.1 43 2.2
3.7 43 2.0
3.4 48 3.5
3.8 48 3.3
3.5 49 3.6
0.66
Orifice Manifold
No. Pressure
43 3.1
43 2.8
43 2.6
43 2.4
43 2.2
43 2.1
48 3.6
48 3.4
49 3.7