![background image](http://html.mh-extra.com/html/carrier/58rav-series/58rav-series_installation-start-up-and-operating-instructions-manual_2562846013.webp)
a. Place duct thermometers in return and supply ducts as near
furnace as possible. Be sure thermometers do not "see" heat
exchangers so that radiant heat does not affect thermometer
readings. This is particularly important with straight-run
ducts.
b. When thermometer readings stabilize, subtract return-air
temperature from supply-air temperature to determine tem-
perature rise.
c. Adjust air temperature rise by adjusting blower speed.
Increase blower speed to reduce temperature rise. Decrease
blower speed to increase temperature rise.
Disconnect the electrical power before changing the speed
tap. Failure to follow this warning could result in personal
injury.
d. To change blower motor speed selections for heating mode,
remove blower motor lead from control board HEAT
terminal. (See Fig. 11.) Select desired blower motor speed
lead from 1 of the other terminals and relocate it to HEAT
terminal. See Table 10 for lead color identification. Recon-
nect original lead on SPARE terminal.
Follow this same procedure for proper selection of COOL
speed selection.
Table 7—Model 58RAV Orifice Size and Manifold Pressure for Correct Input Rate*
(Tabulated Data Based on Altitude Up to 2000 ft and 23,000 Btuh Per Burner)
GAS HEAT VALUE
(BTU/CU FT)
SPECIFIC GRAVITY OF NATURAL GAS
0.56
0.58
0.60
0.62
0.64
0.66
0.68
0.70
0.72
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
Orf
No.
Mnfld
Press.
860
40
41
—
3.2
3.5
—
40
41
39
3.3
3.6
—
40
41
39
3.4
3.7
3.2
40
41
39
3.5
3.8
3.3
40
38
39
3.7
3.2
3.4
40
38
39
3.8
3.3
3.5
—
38
39
—
3.4
3.6
37
38
39
3.2
3.5
3.8
37
38
—
3.2
3.6
—
875
—
41
42
—
3.3
3.7
40
41
—
3.2
3.5
—
40
41
—
3.3
3.6
—
40
41
39
3.4
3.7
3.2
40
41
39
3.5
3.8
3.3
40
38
39
3.6
3.2
3.4
40
38
39
3.8
3.3
3.5
—
38
39
—
3.4
3.6
—
38
39
—
3.4
3.7
890
—
41
42
—
3.2
3.6
—
41
42
—
3.4
3.7
40
41
—
3.2
3.5
—
40
41
—
3.3
3.6
—
40
41
39
3.4
3.7
3.2
40
41
39
3.5
3.8
3.3
40
—
39
3.6
—
3.4
40
38
39
3.7
3.2
3.5
40
38
39
3.8
3.3
3.6
905
—
—
42
—
—
3.5
—
41
42
—
3.2
3.6
—
41
42
—
3.4
3.7
40
41
—
3.2
3.5
—
40
41
—
3.3
3.6
—
40
41
39
3.4
3.7
3.2
40
41
39
3.5
3.8
3.3
40
—
39
3.6
—
3.4
40
38
39
3.7
3.2
3.5
920
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
41
42
—
3.2
3.6
—
41
42
—
3.4
3.7
40
41
42
3.2
3.5
3.8
40
41
—
3.3
3.6
—
40
41
39
3.4
3.7
3.2
40
41
39
3.5
3.8
3.3
40
—
39
3.6
—
3.4
935
42
—
—
3.3
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
—
42
—
41
3.6
—
3.2
42
—
41
3.7
—
3.4
42
40
41
3.8
3.2
3.5
—
40
41
—
3.3
3.6
39
40
41
3.2
3.4
3.7
39
40
41
3.3
3.5
3.8
950
42
—
—
3.2
—
—
42
—
—
3.3
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
—
42
—
41
3.6
—
3.2
42
—
41
3.7
—
3.3
42
40
41
3.8
3.2
3.5
—
40
41
—
3.3
3.6
39
40
41
3.2
3.4
3.7
965
—
43
—
—
3.7
—
42
—
—
3.2
—
—
42
—
—
3.3
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
—
42
—
41
3.6
—
3.2
42
—
41
3.7
—
3.3
42
40
41
3.8
3.2
3.4
—
40
41
—
3.3
3.5
980
—
43
—
—
3.6
—
—
43
—
—
3.7
—
42
—
—
3.2
—
—
42
—
—
3.3
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
—
42
—
41
3.6
—
3.2
42
—
41
3.7
—
3.3
42
44
41
3.8
3.2
3.4
995
—
43
—
—
3.5
—
—
43
—
—
3.6
—
—
43
—
—
3.8
—
42
—
—
3.2
—
—
42
—
—
3.3
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
—
42
—
41
3.6
—
3.2
42
—
41
3.7
—
3.3
1010
—
43
—
—
3.4
—
—
43
—
—
3.5
—
—
43
—
—
3.6
—
—
43
—
—
3.6
—
42
—
—
3.2
—
—
42
—
—
3.3
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
—
42
—
41
3.6
—
3.2
1025
—
43
44
—
3.3
3.8
—
43
—
—
3.4
—
—
43
—
—
3.5
—
—
43
—
—
3.7
—
—
43
—
—
3.8
—
42
—
—
3.2
—
—
42
—
—
3.3
—
—
42
—
—
3.4
—
—
42
—
—
3.5
—
—
1035
—
43
44
—
3.2
3.7
—
43
44
—
3.3
3.8
—
43
—
—
3.4
—
—
43
—
—
3.6
—
—
43
—
—
3.7
—
—
43
—
—
3.8
—
42
—
—
3.2
—
—
42
—
—
3.3
—
—
42
—
—
3.4
—
—
1055
—
—
44
—
—
3.6
—
43
44
—
3.2
3.7
—
43
44
—
3.3
3.8
—
43
—
—
3.5
—
—
43
—
—
3.6
—
—
43
—
—
3.7
—
—
43
—
—
3.8
—
42
—
—
3.2
—
—
42
—
—
3.3
—
—
1070
—
—
44
—
—
3.5
—
—
44
—
—
3.6
—
43
44
—
3.3
3.7
—
43
44
—
3.4
3.8
—
43
—
—
3.5
—
—
43
—
—
3.6
—
—
43
—
—
3.7
—
—
43
—
—
3.8
—
42
—
—
3.2
—
—
1085
—
44
—
3.4
—
44
—
3.5
43
44
3.2
3.6
43
44
3.3
3.7
43
—
3.4
—
43
—
3.5
—
43
—
3.6
—
43
—
3.7
—
43
—
3.8
—
1100
—
44
—
3.3
—
44
—
3.4
—
44
—
3.5
43
44
3.2
3.6
43
44
3.3
3.7
43
—
3.4
—
43
—
3.5
—
43
—
3.6
—
43
—
3.7
—
*For size 135-20 only, deduct 0.1-in. wc from manifold pressure shown in table due to 22,500 Btuh per burner input. If resultant manifold pressure falls below 3.2-in. wc,
change orifice size.
13