Carrier 48TC D/E24 Series - Page 25

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Table 5 — Natural Gas Manifold Pressure Ranges
Table 6 — LP Manifold Pressure Ranges
Table 7 lists typical
3
/
4
-in. NPT (National Pipe Thread) field sup-
plied pipe fittings required for Thru-Base gas supply, starting from
the unit gas valve (see Fig. 26).
Pipe gas supply into 90 degree elbow item 15 (see Table 7)
through the hole in the unit basepan.
For typical
3
/
4
-in. NPT field supplied fittings required for NON
Thru-Base gas supply starting from the unit gas valve, omit
items 14 and 15 from Table 7 and pipe gas supply into Tee. See
Fig. 27.
Fig. 26 — Gas Supply Line Piping with Thru-Base
Fig. 27 — Gas Supply Line Piping
Table 7 — Typical
3
/
4
-in. NPT Field Supplied Piping
Parts
Install a gas supply line that runs to the unit heating section. Refer
to the NFPA 54/NFGC or equivalent code for gas pipe sizing data.
Do not use a pipe smaller than the size specified. Size the gas sup-
ply line to allow for a maximum pressure drop of 0.5 in. wg
(124 Pa) between gas regulator source and unit gas valve connec-
tion when unit is operating at high-fire flow rate.
The gas supply line can approach the unit in two ways: horizontal-
ly from outside the unit (across the roof), or through unit basepan.
Observe clearance to gas line components per Fig. 28.
UNIT MODEL UNIT SIZE HIGH FIRE LOW FIRE
48TC**
17, 20, 24,
28, 30
3.0 in.wg
(747 Pa)
2.0 in.wg
(498 Pa)
UNIT MODEL UNIT SIZE HIGH FIRE LOW FIRE
48TC**
17, 20, 24,
28, 30
11.0 in.wg
(2737 Pa)
7.3 in.wg
(1816 Pa)
CAUTION
EQUIPMENT DAMAGE
Failure to follow this caution may result in equipment damage.
When connecting the gas line to the unit gas valve, the installer
MUST use a backup wrench to prevent damage to the valve.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
ITEM QTY DESCRIPTION
1 1 90° Street Elbow
2 1 5 in. Long Nipple
3 1 Ground - Joint Union
4 1 3 in. Long Nipple
5 1 90° Elbow
6 1 12 in. Long Nipple
7 1 90° Elbow
8 1 3 in. Long Nipple
9 1Tee
10 1 4 in. Long Nipple (Sediment Trap)
11 1Cap
12 13
1
/
2
in. Long Nipple
13 1NIBCO
*
Ball Valve (PN: GB30)
14 1 8 in. Long Nipple
15 1 90° Elbow
13
12
11
10
9
8
7
6
5
4
3
2
1