Sterling RT - Manual (Page 10)

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D3726
The appliance must be isolated from the gas supply
piping system by closing its individual manual shutoff
valve during any pressure testing of the gas supply
piping system at test pressure equal to or less than
1/2 psig (3.5 kPa).
For additional piping information, refer to the latest
edition of the National Fuel Gas Code ANSI Z233.1
(NFPA 54).
Figure 9a - Drip Leg Installation
Figure 9b - Field Piping Recommendations
DUCT SPECIFICATIONS
Ductwork connected to duct furnaces should have
removable access panels on both the upstream and
downstream sides of the unit. These openings should
be accessible when the unit is installed, and should be
sized so that smoke or refl ected light can be observed
inside the casing to indicate the presence of leaks in
the heating equipment. The covers of the openings
should be attached in a manner that prevents leaks. Ductwork which is outdoors must be insulated and
sealed to prevent water from entering either furnace
or building through the duct. Do not alter the flange
connection for the duct attachment; air may bypass
and cause combustion problems. Be sure to properly
seal to avoid any air leakage (refer to Figures 1 and 2).
GAS CONNECTIONS
All gas piping should be installed in accordance with
local codes. It is required that a ground union be installed
adjacent to the manifold for easy servicing. On vertical
runs, a drip leg should be provided upstream of the
control manifold (see fi gure 9a). An additional shut-off
must be located externally of the jacket enclosure where
required by local code. The location of this valve must
comply with the local codes. A 1/8 inch NPT plugged
tapping, accessible for test gauge connection, must be
installed immediately upstream of the gas supply
connection to the unit. Field gas piping recommendations
are shown in Figure 9b.
It is recommended that the gas piping not be installed
through the bottom of the duct furnace bottom panel. If
piping must penetrate the duct furnace bottom panel, it
must be sealed to prevent water leakage.
To avoid equipment damage or
possible personal injury, do not connect gas
piping to this unit until a supply line pressure/
leak test has been completed. Connecting the
unit before completing the pressure/leak test
may damage the unit gas valve and result in a
fi re hazard.
Do not rely on a shutoff valve to
isolate the unit while conducting gas pressure/leak
tests. These valves may not be completely shut off,
exposing the unit gas valve to excessive pressure
and damage. Do not overtighten the inlet gas piping.
This may cause stresses that would crack the valve.
Never use an open flame to
detect gas leaks. Explosive conditions may exist
which would result in personal injury or death.
The gas line should be supported so that no strain is
The gas line should be supported so that no strain
is placed on the unit. Pipe compounds which are not
soluble to liquid petroleum gases should be used on
threaded joints.
The appliance and its individual shutoff valve must be
disconnected from the gas supply piping system during
any pressure testing of that system at test pressure in
excess of 1/2 psig (3.5 kPa).
D3726
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