![background image](http://html.mh-extra.com/html/carrier/58dxt/58dxt_operating-instructions-manual_2562771007.webp)
Step 5—Filter Arrangement
Never operate unit without a filter or with filter access door
removed. A failure to follow this warning could result in fire,
personal injury, or death.
The 2 factory-supplied filters are shipped in the blower compart-
ment. After return-air duct has been connected to furnace, install
filters in a V-formation inside return-air plenum. (See Fig. 8.)
Step 6—Gas Piping
Gas piping must be installed in accordance with national and local
codes. Refer to the NFGC.
Canadian installations must be installed in accordance with NSC-
NGPIC and all authorities having jurisdiction.
The gas supply line should be a separate line directly from the
meter to the furnace, if possible. Refer to Table 4 for recom-
mended gas pipe sizing. Risers should be used to connect to the
furnace and to the meter.
If 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.
Use the proper length of pipes to avoid stress on gas control
manifold. A failure to follow this warning could result in a
gas leak causing fire, explosion, personal injury, or death.
Use a backup wrench at furnace gas control when connecting
gas pipe to furnace to avoid damaging gas controls or
manifold.
Table 3—Opening Dimensions (In.)
FURNACE
CASING
WIDTH
APPLICATION
PLENUM OPENING
FLOOR OPENING
A
B
C
D
14-3/16
Non-Combustible Flooring
12-11/16
19
13-3/8
19-5/8
Combustible Flooring Using KGASB Subbase
11-13/16
19
13-7/16
20-3/8
Combustible Flooring with CD5 or CK5 Coil Assembly or
KCAKC Coil Box
12-5/16
19
13-5/16
20
17-1/2
Non-Combustible Flooring
16
19
16-5/8
19-5/8
Combustible Flooring Using KGASB Subbase
15-1/8
19
16-3/4
20-3/8
Combustible Flooring with CD5 or CK5 Coil Assembly or
KCAKC Coil Box
15-1/2
19
16-1/2
20
21
Non-Combustible Flooring
19-1/2
19
20-1/8
19-5/8
Combustible Flooring Using KGASB Subbase
18-5/8
19
20-1/4
20-3/8
Combustible Flooring with CD5 or CK5 Coil Assembly or
KCAKC Coil Box
19
19
20
20
Fig. 5—Floor and Plenum Opening Dimensions
A96283
PLENUM
OPENING
C
A
B
D
FLOOR
OPENING
7