Carrier 58MVP080 Installation, Start-Up, And Operating Instructions Manual page 43

ON/OFF
SWITCH
INLET
PRESSURE
TAP
BURNER
ENCLOSURE
REFERENCE
PRESSURE TAP
MANIFOLD
PRESSURE
Fig. 50—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.
UNITED STATES
At altitudes above 2000 ft, this furnace has been approved
for a 2 percent derate for each 1000 ft above sea level. See
Table 13 for derate multiplier factor and example.
EXAMPLE: 100,000 BTUH INPUT FURNACE INSTALLED AT
4300 FT.
Derate
Furnace Input Rate
X Multiplier
at Sea Level
Factor
100,000 X 0.91
LOW-FIRE
ADJUSTMENT
ALLEN SCREW
(UNDER CAP)
HIGH-FIRE
ADJUSTMENT
ALLEN SCREW
(UNDER CAP)
TAP
A97386
BURNER
ORIFICE
A93059
Furnace Input Rate
= at Installation
Altitude
= 91,000
BURNER FLAME
MANIFOLD
Fig. 51—Burner Flame
Table 13—Altitude Derate Multiplier for U.S.A.
ALTITUDE
(FT) DERATE
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.
CANADA
At installation altitudes from 2000 to 4500 ft, this furnace
must be derated 5 percent by an authorized Gas Conversion
Station or Dealer. To determine correct input rate for
altitude, see example above and use 0.95 as derate multi-
plier factor.
b. Reinstall burner box cover.
NOTE: Clocking gas input rate MUST always be performed with
the burner box cover INSTALLED.
c. Check that gas valve adjustment caps are in place for
proper input to be clocked.
d. Obtain yearly heat value average for local gas supply.
NOTE: Be sure heating value of gas used for calculations is
correct for your altitude. Consult local gas utility for altitude
adjustment of gas heating value.
e. Check and verify orifice size in furnace. NEVER ASSUME
THE ORIFICE SIZE. ALWAYS CHECK AND VERIFY.
f. Turn off all other gas appliances and pilots.
g. Move setup switch SW-2 to ON position. (See Fig. 25.)
This keeps furnace locked in low-heat operation.
43
BURNER
% OF DERATE MULTIPLIER
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
A89020