28
RT-SVX077B-EN
Component Description
I
Pipe Fitting (3/4-in. x 2 1/2-in.)
J 90° Street Elbow
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 6, p. 28 and
Table 7, p. 28).
Table 6. Gas heat data - supply and manifold
pressure requirements – two-stage gas
YZJ150*
YZJ(180-300)*
Heating Input Rate – Btu/h
150,000-
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 7. Gas heat data - supply and manifold
pressure requirements - modulating gas
Digit 10 = B models
Heating Input Rate — Btu/h
250,000 – 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
Condensate Drain Configuration
WARNING
Hazardous Voltage!
Failure to disconnect power before servicing could
result in death or serious injury.
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Verify that no power is
present with a voltmeter.
An evaporator condensate drain connection is provided on
each unit. Refer to the ductwork section in the Installation
chapter for the appropriate drain location.
A condensate trap must be installed at the unit due to the
drain connection being on the negative pressure side of
the fan. Install the p-trap using the guidelines in .
A condensate drain line must be connected to the p-trap.
Pitch the drain lines at least 1/2-inch for every 10 feet of
horizontal run to assure proper condensate flow. Do not
allow the horizontal run to sag causing a possible double
trap condition. This can result in condensate backup due to
air lock.
Installation
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