Bottom Closure Panel; Gas Piping - Carrier 58MXA Installation, Start-Up, And Operating Instructions Manual

NOTE: Remove and discard bottom closure panel when bottom
inlet is used.
Step 6—Bottom Closure Panel
These furnaces are shipped with bottom enclosure panel installed
in bottom return-air opening. This panel MUST be in place when
side return air is used.
To remove bottom closure panel, perform following:
1. Tilt or raise furnace and remove 2 screws holding front filler
panel. (See Fig. 20.)
FRONT FILLER
PANEL
Fig. 20—Removing Bottom Closure Panel
2. Rotate front filler panel downward to release holding tabs.
3. Remove bottom closure panel.
4. Reinstall front filler panel and screws.
Step 7—Gas Piping
Gas piping must be installed in accordance with national and local
codes. Refer to current edition of NFGC. Canadian installations
must be made in accordance with NSCNGPIC and all authorities
having jurisdiction. Gas supply line should be a separate line
running directly from meter to furnace, if possible. Refer to Table
3 for recommended gas pipe sizing. Risers must be used to connect
to furnace and to meter. Support all gas piping with appropriate
straps, hangers, etc. Use a minimum of 1 hanger every 6 ft. Joint
compound (pipe dope) should be applied sparingly and only to
male threads of joints. Pipe dope must be resistant to propane gas.
Connect gas pipe to furnace using a backup wrench to avoid
damaging gas controls.
Gas valve shutoff switch MUST be facing forward or tilted
upward. Failure to follow this warning could result in
property damage or death.
Never purge a gas line into a combustion chamber. Never use
matches, candles, flame, or other sources of ignition for
purpose of checking leakage. Use a soap-and-water solution
to check for leakage. A failure to follow this warning could
result in fire, explosion, personal injury, or death.
Install a sediment trap in riser leading to furnace. Trap can be
NOMINAL
* Cubic ft of gas per hr for gas pressures of 0.5 psig (14–in. wc) or less and a
pressure drop of 0.5–in wc (based on a 0.60 specific gravity gas).
Ref: Table 10–2 NFGC.
installed by connecting a tee to riser leading to furnace so
straight-through section of tee is vertical. Then connect a capped
BOTTOM
nipple into lower end of tee. Capped nipple should extend below
CLOSURE
PANEL
level of gas controls. Place a ground joint union between gas
control manifold and manual gas shutoff valve. (See Fig. 21.)
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An accessible manual shutoff valve MUST be installed upstream
of furnace gas controls and within 6 ft of furnace. A 1/8-in. NPT
plugged tapping, accessible for test gage connection, MUST be
installed immediately upstream of gas supply connection to
furnace and downstream of manual shutoff valve.
NOTE: The gas valve inlet press tap connection is suitable to use
as test gage connection providing test pressure DOES NOT exceed
maximum 0.5 psig (14-in. wc) stated on gas valve. (See Fig. 44.)
Piping should be pressure tested in accordance with local and
national plumbing and gas codes before furnace is attached. In
Canada, refer to current edition of NSCNGPIC. If pressure
18
Use proper length of pipe to avoid stress on gas control
manifold. Failure to follow this warning could result in a gas
leak resulting in fire, explosion, personal injury, or death.
Table 3—MAXIMUM CAPACITY OF PIPE*
IRON INTERNAL
PIPE DIAMETER
SIZE (IN.)
10
(IN.)
1/2 0.622 175
3/4 0.824 360
1 1.049 680
1-1/4 1.380 1400
1-1/2 1.610 2100
GAS
SUPPLY
MANUAL
SHUTOFF
VALVE
(REQUIRED)
SEDIMENT
TRAP
UNION
Fig. 21—Typical Gas Pipe Arrangement
If a flexible connector is required or allowed by authority
having jurisdiction, black iron pipe shall be installed at gas
valve and extend a minimum of 2 in. outside furnace casing.
LENGTH OF PIPE (FT)
20 30 40 50
120 97 82 73
250 200 170 151
465 375 320 285
950 770 660 580
1460 1180 990 900
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