Carrier 58SMA Operating Instructions Manual page 36

INLET
PRESSURE TAP
Fig. 40—Redundant Automatic Gas Valve
DO NOT redrill orifices. Improper drilling (burrs, out-of-
round holes, etc.) can cause excessive burner noise and
misdirection of burner flames. This can result in flame
impingement of burners and heat exchangers causing failures.
d. Replace gas valve regulator adjustment screw cap.
e. Replace burner enclosure front and verify adjusted gas
input rate using method outlined in item 3.
f. Look through sight glass in burner enclosure and check
burner flame. Burner flame should be clear blue, almost
transparent. (See Fig. 41.)
3. Verify natural gas input rate by clocking gas meter.
NOTE: Be sure all pressure tubing, combustion-air and vent
pipes, and burner enclosure front are in place when checking input
by clocking gas meter.
NOTE: High-Altitude Adjustment
ON AND
OFF SWITCH
GAS
PRESSURE
REGULATOR
ADJUSTMENT
BURNER
ENCLOSURE
REFERENCE
PRESSURE
TAP
MANIFOLD
PRESSURE TAP
A95622
BURNER
ORIFICE
A93059
BURNER FLAME
MANIFOLD
Fig. 41—Burner Flame
United States
At altitudes above 2000 ft, this furnace has been approved for a 2%
derate for each 1000 ft above sea level. See Table 8 for derate
multiplier factor.
Table 8—Altitude Derate Multiplier for U.S.A.
ALTITUDE
(FT)
0—2000
2001—3000
3001—4000
4001—5000
5001—6000
6001—7000
7001—8000
8001—9000
9001—10,000
* Derate multiplier factor is based on midpoint altitude for altitude range.
EXAMPLE:
88,000 Btuh input furnace installed at 4300 ft.
Furnace Input
Rate at X
Sea Level
88,000 X 0.91 = 80,080
Canada
At installation altitudes from 2000 to 4500 ft, this furnace must be
derated 5% by an authorized Gas Conversion Station. To deter-
mine correct input rate for altitude, see example above and use
0.95 as derate multiplier factor.
a. Turn off all other gas appliances and pilots.
b. Start furnace and let operate for 3 minutes.
c. Measure time (in sec) for gas meter test dial to complete 1
revolution.
d. Refer to Table 9 for cu ft of gas per hr.
e. Multiply gas rate (cu ft/hr) X heating value (Btu/cu ft)
using natural gas heating value from local gas
utility/supplier.
36
BURNER
% OF DERATE MULTIPLIER
DERATE FACTOR FOR U.S.A*
0 1.00
4—6 0.95
6—8 0.93
8—10 0.91
10—12 0.89
12—14 0.87
14—16 0.85
16—18 0.83
18—20 0.81
Derate Furnace Input Rate
Multiplier = at Installation
Factor Altitude
A89020