Bryant G Series Installation & Operating Instructions Manual page 12

TABLE 6—MODEL 395CAV ORIFICE SIZE AND MANIFOLD PRESSURE FOR CORRECT INPUT RATE
(Tabulated Data Based on Altitude Up to 2000 Ft and 22,000 Btuh Per Burner)
GAS
HEAT 0.56
VALUE
Orf Mnfld
(BTU/CU FT)
No. Press.
41 3.2
860 42 3.6
— —
42 3.4
875 — —
— —
42 3.3
890 — —
— —
42 3.2
905 — —
— —
43 3.8
920
— —
43 3.7
935
— —
43 3.6
950
— —
43 3.4
965
— —
44 3.8
980
43 3.3
44 3.7
995
43 3.2
44 3.6
1010
— —
44 3.5
1025
— —
44 3.4
1040
— —
44 3.3
1055
— —
44 3.2
1070
— —
45 3.8
1085
— —
45 3.7
1100
— —
b. Check gas input rate by clocking gas meter.
(1.) Obtain average yearly heat value for local gas
supply.
(2.) Check and verify orifice size in furnace. NEVER
ASSUME THE
CHECK AND VERIFY.
CAUTION: DO NOT redrill burner orifices. Improper
drilling (burrs, out of round, etc.) can cause excessive
burner operating noise and misdirection of burner flames.
This could result in flame impingement on burners and
heat exchanger surfaces, leading to potential failures.
(3.) Turn off all other gas appliances and pilots.
(4.) Start furnace and let run for 3 minutes.
(5.) Measure time (in sec) for gas meter to complete 1
revolution.
(6.) Refer to Table 7 for cu ft of gas per hr.
(7.) Multiply gas rate (cu ft/hr) by heating value (Btu/cu
ft).
SPECIFIC GRAVITY OF NATURAL GAS
0.58 0.60
Orf Mnfld Orf Mnfld Orf
No. Press. No. Press. No.
41 3.3 41 3.4 41
42 3.7 42 3.8 40
— — 40 3.2 —
41 3.2 41 3.3 41
42 3.6 42 3.7 42
— — — — 40
42 3.4 41 3.2 41
— — 42 3.6 42
— — — — —
42 3.3 42 3.4 41
— — — — 42
— — — — —
42 3.2 42 3.3 42
— — — — —
43 3.8 42 3.2 42
— — — — —
43 3.7 43 3.8 42
— — — — —
43 3.6 43 3.7 43
— — — — —
42 3.5 43 3.6 43
— — — — —
44 3.8 43 3.5 43
43 3.4 — — —
44 3.7 44 3.8 43
43 3.3 43 3.4 —
44 3.6 44 3.7 43
43 3.2 43 3.3 —
44 3.5 44 3.6 44
— — 43 3.2 43
44 3.4 44 3.5 44
— — — — 43
44 3.3 44 3.4 44
— — — — —
44 3.2 44 3.3 44
— — — — —
45 3.8 44 3.2 44
— 3.4 — — —
ORIFICE SIZE. ALWAYS
0.62 0.64 0.66
Mnfld Orf Mnfld Orf
Press. No. Press. No.
3.5 41 3.7 41
3.3 39 3.2 39
— 40 3.4 40
3.4 41 3.5 41
3.8 40 3.3 39
3.2 — — 40
3.3 41 3.4 41
3.7 42 3.8 40
— — — —
3.2 41 3.3 41
3.6 42 3.7 42
— — — —
3.4 41 3.2 41
— 42 3.5 42
3.3 42 3.4 41
— — — 42
3.2 42 3.3 42
— — — —
3.8 42 3.2 42
— — — —
3.7 43 3.8 42
— — — —
3.6 43 3.7 43
— — — —
3.5 43 3.6 43
— — — —
3.4 43 3.5 43
— — — —
3.7 43 3.4 43
3.3 — — —
3.6 44 3.8 43
3.2 43 3.3 —
3.5 44 3.7 44
— 43 3.2 43
3.4 44 3.6 44
— — — 43
3.4 44 3.5 44
— — — —
EXAMPLE:
Btu heating input = Btu/cu ft X cu ft/hr
Heating value of gas = 1070 Btu/cu ft
Time for 1 revolution of 2 cu ft dial = 72 sec
Gas rate = 100 X 1070 = 107,000 Btuh
(8.) Measured gas input should not exceed gas input on
unit rating plate.
(9.) Proceed to item c to adjust manifold pressure.
c. Adjust gas input.
(1.) Remove regulator adjustment seal cap. (See Fig.
12.)
(2.) Turn adjusting screw counterclockwise to decrease
input. Turn screw clockwise to increase input. DO
NOT set manifold pressure less than 3.2-in. wc or
more than 3.8-in. wc for natural gas. Make any
major adjustments by changing main burner ori-
fices.
—12—
0.68 0.70
Mnfld Orf Mnfld Orf Mnfld
Press. No. Press. No. Press.
3.8 39 3.4 38
3.3 40 3.6 39
3.5 — — 40
3.6 41 3.8 39
3.2 39 3.3 40
3.4 40 3.5 —
3.5 41 3.6 41
3.2 40 3.3 39
— — — 40
3.4 41 3.5 41
3.8 40 3.2 40
— — — —
3.3 41 3.4 41
3.7 42 3.8 40
3.2 41 3.3 41
3.5 42 3.7 42
3.4 41 3.2 41
— 42 3.5 42
3.3 42 3.4 41
— — — 42
3.2 42 3.3 42
— — — —
3.8 42 3.2 42
— — — —
3.7 43 3.8 42
— — — —
3.6 43 3.7 43
— — — —
3.5 43 3.6 43
— — — —
3.4 43 3.5 43
— — — —
3.8 43 3.4 43
3.3 — — —
3.7 44 3.8 43
2.3 43 3.3 —
3.6 44 3.7 44
— 43 3.2 43
0.72
Orf Mnfld
No. Press.
3.2 38 3.3
3.5 39 3.6
3.7 40 3.8
3.3 38 3.2
3.6 39 3.4
— 40 3.7
3.7 41 3.8
3.2 39 3.3
3.4 40 3.5
3.6 41 3.7
3.3 39 3.2
— 40 3.4
3.5 41 3.6
3.2 40 3.3
3.4 41 3.5
3.8 40 3.2
3.3 41 3.4
3.6 42 3.7
3.2 41 3.3
3.5 42 3.6
3.4 41 3.2
— 42 3.5
3.3 42 3.4
— — —
3.2 42 3.3
— — —
3.8 43 3.2
— — —
3.7 43 3.8
— — —
3.6 43 3.7
— — —
3.5 43 3.6
— — —
3.4 43 3.5
— — —
3.8 43 3.4
3.3 — —