RT-SVX092A-EN
55
Table 11. Through-the-base gas pipe assembly for
D.0 and D.1 cabinets (continued)
Component Description
K
Pipe Union
L
Pipe Fitting (3/4-in. x 2 1/2-in.)
M Gas Shut-off Valve
N 90° Street Elbow
O
Pipe Fitting (3/4-in. x 6 1/2-in.)
For detailed through-the-base gas installation instructions,
refer to the Through-the-Base Gas Piping 3 to 25 Tons
Gas/Electric Packaged Units Installation Instructions (ACC-
SVN17*-EN) provided with through-the-base gas
installation kit.
Requirements of Gas Heat
The unit gas train and optional through-the-base gas shut-
off valve are rated at 0.50 PSIG maximum. A pressure
reducing regulator is recommended to prevent this
maximum from being exceeded. These components must
be isolated during field gas piping test that exceed 0.50
PSIG.
Important: It is recommended that the field piping be
capped prior to the unit gas train or optional
through-the-base gas shut-off valve if present.
☐ Gas supply line properly sized and connected to the
unit gas train.
☐ All gas piping joints properly sealed.
☐ Gas piping leak checked with a soap solution. If piping
connections to the unit are complete, do not pressurize
piping in excess of 0.50 PSIG or 14-inch w.c. to prevent
component failure.
☐ Drip leg installed in the gas piping near the unit.
☐ Flue exhaust clear of any obstruction.
☐ Supply and manifold pressures should be checked
during unit commissioning (see Table 12, p. 55 and
Table 13, p. 55).
Table 12. Gas heat data - supply and manifold
pressure requirements – two-stage gas
Description
Y(S,H)K(036-
150)*
Y(S,H)K(180-300)*
Heating Input Rate —
Btu/h
80,000 – 250,000 250,000 320,000 400,000
Minimum Supply Gas
Pressure NG/LP (in. w.c.)
4.5/11.5 4.5/11.5 6/11.5
Maximum Supply Gas
Pressure (in. w.c.)
14
Manifold Gas Pressure –
1st Stage -NG (in. w.c.)
1.8 1.7 1.8 1.7
Manifold Gas Pressure –
2nd Stage -NG (in. w.c.)
3.5 3.3 3.5 3.3
Table 13. Gas heat data - supply and manifold
pressure requirements - modulating gas
(model number digit 10 = B)
Description
Model Number Y(S,H)K
(072-300)*
Heating Input Rate - Btu/h
80,000 – 400,000
Minimum Supply Gas Pressure NG/LP (in. w.c.)
5/11.5
Maximum Supply Gas Pressure (in. w.c.)
14
Manifold Gas Pressure - Full Gas Input Rate - NG/
LP (in. w.c.)
3.5/10
Modulating Gas Heat
For models Y(S,H)K (072,090,102,120,150)***B(H,L):
1. Confirm the vertical slide bracket on the DAS vertical
tube is positioned to block all the hole(s) for downflow
configuration.
Note: Number of holes will vary. Verify bracket is
covering all holes in the vertical tube, regardless
of quantity.
2. Removal of horizontal duct supply cover is required to
view DAS tubing located behind the heat exchanger
tubes.
Figure 79. Downflow position shown
Bracket adjustment
screw
Vertical slide bracket
downflow position
Installation
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