Carrier 58PAV - Manual (Page 10)

Table 6—Model 58PAV 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 VALUE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.56
Orf
No.
Mnfld
Press.
0.58
Orf
No.
Mnfid
Press.
0.60
Orf
No.
Mnfld
Press.
0.62
Orf
No.
Mnfld
Press.
0.64
Orf
No.
Mnfld
Press.
0.66
Orf
No.
Mnfld
Press.
0.68
Orf
No.
Mnfld
Press.
0.70
Orf
No.
Mnfld
Press.
0.72
Orf
No.
Mnfld
Press.
860
41
42 3.2
3.6 41
42 3.3
3.7 41
42
40 3.4
3.8
3.2 41
40 3.5
3.3 41
39
40 3.7
3.2
3.4 41
39
40 3.8
3.3
3.5 39
40 3.4
3.6 38
39
40 3.2
3.5
3.7 38
39
40 3.3
3.6
3.8
42 3.4
875
41
42 3.2
3.6 41
42 3.3
3.7 41
42
40 3.4
3.8
3.2 41
40 3.5
3.3 41
39
40 3.6
3.2
3.4 41
39
40 3.8
3.3
3.5 39
40 3.3
3.6 38
39
40 3.2
3.4
3.7
42 3.3 42 3.4
890
41
42 3.2
3.6 41
42 3.3
3.7 41
42 3.4
3.8 41
40 3.5
3.2 41
40 3.6
3.3 41
39
40 3.7
3.2
3.4 41
39
40 3.8
3.3
3.5
42 3.2 42 3.3 42 3.4
905
41
42 3.2
3.6 41
42 3.3
3.7 41
42 3.4
3.8 41
40 3.5
3.2 41
40 3.6
3.3 41
39
40 3.7
3.2
3.4
920
43 3.8 42 3.2 42 3.3 42 3.4 41
42 3.2
3.5 41
42 3.3
3.7 41
42 3.4
3.8 41
40 3.5
3.2 41
40 3.6
3.3
935
43 3.7 43 3.8 42 3.2 42 3.3 42 3.4 41
42 3.2
3.5 41
42 3.3
3.7 41
42 3.4
3.8 41
40 3.5
3.2
950
43 3.6 43 3.7 43 3.8 42 3.2 42 3.3 42 3.4 41
42 3.2
3.5 41
42 3.3
3.6 41
42 3.4
3.7
965
43 3.4 43 3.6 43 3.7 43 3.8 42 3.2 42 3.3 42 3.4 41
42 3.2
3.5 41
42 3.3
3.6
980
44
43 3.8
3.3 42 3.5 43 3.6 43 3.7 43 3.8 42 3.2 42 3.3 42 3.4 41
42 3.2
3.5
995
44
43 3.7
3.2 44
43 3.8
3.4 43 3.5 43 3.6 43 3.7 43 3.8 42 3.2 42 3.3 42 3.4
1010
44 3.6 44
43 3.7
3.3 44
43 3.8
3.4 43 3.5 43 3.6 43 3.7 43 3.8 42 3.2 42 3.3
1025
44 3.5 44
43 3.6
3.2 44
43 3.7
3.3 43 3.4 43 3.5 43 3.6 43 3.7 43 3.8 43 3.2
1040
44 3.4 44 3.5 44
43 3.6
3.2 44
43 3.7
3.3 43 3.4 43 3.5 43 3.6 43 3.7 43 3.8
1055
44 3.3 44 3.4 44 3.5 44
43 3.6
3.2 44
43 3.8
3.3 43 3.4 43 3.5 43 3.6 43 3.7
1070
44 3.2 44 3.3 44 3.4 44 3.5 44
43 3.7
3.2 44
43 3.8
3.3 43 3.4 43 3.5 43 3.6
1085
45 3.8 44 3.2 44 3.3 44 3.4 44 3.6 44
43 3.7
2.3 44
43 3.8
3.3 43 3.4 43 3.5
1100
45 3.7 45 3.8
3.4 44 3.2 44 3.4 44 3.5 44 3.6 44
43 3.7
3.2 44
43 3.8
3.3 43 3.4
(6.) Follow heat value and specific gravity lines to point of
intersection. Find orifice size and manifold pressure
settings for proper operation at given natural gas
conditions.
EXAMPLE:
Heat value = 1070
Btu/cu ft specific gravity = 0.58
Therefore; Orifice No. 44 *
Manifold pressure = 3.3-in. wc
* The furnace is shipped with No. 43 orifices. Therefore, in
this example, all main burner orifices must be changed and
manifold pressure must be adjusted.
Д 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
impingment on burners and heat exchanger surfaces, leading
to potential failures.
(7.) Proceed to item c. to adjust manifold pressure,
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 ORIFICE SIZE. ALWAYS CHECK
AND VERIFY.
(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).
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.
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