Carrier 58MTA Installation, Start-Up, And Operating Instructions Manual page 27

SETUP SWITCHES
LOW-HEAT ONLY AND
BLOWER OFF-DELAY
24-V-THERMOSTAT
TERMINALS
HUMIDIFIER TERMINAL
(24-VAC 0.5 AMP MAX.)
3-AMP FUSE
LED OPERATION &
DIAGNOSTIC LIGHT
115-VAC (L2) NEUTRAL
CONNECTIONS
HI HEAT
LO HEAT
BLOWER SPEED
SELECTION TERMINALS
FURNACE
NOT IN
HORIZONTAL
SECTION
Fig. 33—Combustion-Air and Vent Pipe Diameter
Transition Location and Elbow Configuration
NOTE: The minimum combustion-air and vent pipe length (each)
for these furnaces is 5 ft. Short pipe lengths (5-8 ft) may discharge
water droplets. These droplets may be undesirable, and a 12-in.
minimum offset pipe section is recommended, as shown in Fig. 35,
to reduce excessive droplets from exiting vent pipe outlet.
Combustion-Air and Vent Pipe Diameter
Determine combustion-air and vent pipe diameter.
1. Using Table 7, individually determine the smallest
combustion-air and vent pipe diameters allowed for each pipe.
Pick the larger of these 2 pipe diameters and use this diameter
for both combustion-air and vent pipes.
TWINNING AND/OR
COMPONENT TEST
TERMINAL
LHT
OFF
DLY
TEST/TWIN
HUM
0.5-AMP024 VAC
FUSE 3-AMP
SEC-1 SEC-2
EAC-2 NEUTRAL-L2
BLW
BHI/LOR BHT/CLR
COOL 1-AMP@115 VAC
SPARE-1 SPARE-2 EAC-1
SPARE-1
COOL
SPARE-2
EAC-1 TERMINAL
(115-VAC 1.0 AMP MAX.)
Fig. 32—Control Center
PIPE DIAMETER
TRANSITION IN
VERTICAL SECTION
A93034
ACRDJ - AIR CONDITIONING
RELAY DISABLE JUMPER
BLWR
PR-1
HSI HI LO
115-VAC (L1) LINE
VOLTAGE CONNECTION
2. When installing vent systems of short pipe length, use the
smallest allowable pipe diameter. Do not use pipe size greater
than required or incomplete combustion, flame disturbance, or
flame sense lockout may occur.
NOTE: Do not count elbows or pipe sections in terminations or
within furnace. See shaded areas in Fig. 37, 38, 39, 40, and 41.
EXAMPLE: An 080-12 size furnace located in Indianapo-
lis, elevation 650 ft above sea level, could be installed in an
application requiring 3 elbows and 32 ft of vent pipe, along
with 5 elbows and 34 ft of combustion-air pipe. Table 7
indicates this application would allow a 2-in. diameter vent
pipe, but require a 2-1/2 in. diameter combustion air pipe
(2-in. pipe is good for 35 ft with 3 elbows, but only 30 ft
with 5 elbows). Therefore, 2-1/2 in. diameter pipe must be
used for both vent and combustion-air pipes since larger
required diameter must always be used for both pipes. If
same installation were in Albuquerque, elevation 5250 ft
above sea level, installation would require 2-1/2 in. vent
pipe and combustion-air pipe. At 5001- to 6000-ft eleva-
tion, 2-in. pipe is only good for 17 ft with 5 elbows, and
2-1/2 in. pipe is good for 70 ft with 5 elbows.
Combustion-Air and Vent Pipe Attachment
NOTE: All pipe joints must be cemented except attachment of
combustion-air pipe to inlet housing connection, since it may be
necessary to remove pipe for servicing.
1. Attach combustion-air pipe to furnace as follows:
27
TRANSFORMER 24-VAC
CONNECTIONS
PL1 - LOW VOLTAGE MAIN
HARNESS CONNECTOR
PL3
PL2 - HOT SURFACE
IGNITER & INDUCER
MOTOR CONNECTOR
A02017