Water Connections And Piping - American Standard TGBWF090A93AVA Installation Manual

3.4 Water Connections and Piping

Systems
Overview
For good operation and long life of the boiler, the
piping system must be well proportioned and always
complete with all those accessories that provide
optimum system performance, highest effi ciency, and
reliable operation.
Air Vents/Boiler Drain
If the supply and return pipes follow a path where air
pockets could form in certain places, it is advisable
to install an air vents at these points. Also, install a
discharge device at the lowest point in the system to
allow complete draining of the system.
Flow Check Valve
If the boiler is installed at the lowest point of a single
loop system or hydronic coils are used upstream of
air conditioning coils, a fl ow check valve should be
installed to prevent the natural migration of hot
water through the system in the circulator's off cycle.
Low Water Cutoff
The installer of the boiler is required to provide a low
water cutoff switch when installing the boiler above
the distribution system. Consult local codes which
may require a low water cutoff for all installations
regardless of boiler location. The low water cut off
switch should discontinue burner operation until
proper water level is achieved.
Boiler Protection
The cases where this boiler is installed on systems
with large volumes of water (for example - retro fi tted
gravity system), the installer is required to use one
of the methods of boiler protection described in this
manual under "Typical System Piping Diagrams" to
protect the system.
Figure 7
FLUE GAS
SPILL SWITCH
SENSOR
RETURN 1" NPT
18-CG01D1-4
12
Minimum boiler return temperature is 110°F.
NOTE: Do not use the water system pipes to ground
electrical appliances.
System Water
Before installation, carefully fl ush all the pipes
of the system with water to remove residues or
impurities that could affect proper operation of the
system. Additives and cleaning solutions are not
recommended. The installing dealer is required to
test the boiler's water source for water hardness.
Water hardness greater than 14 grains per gallon
of water will require water treatment to reduce the
affect of hard water on the boiler. In the presence
of water harder than 14 grains per gallon, we
recommend the use of suitably conditioned water in
order to avoid possible scaling in the boiler, caused
by hard water, or corrosion produced by aggressive
water. It should be remembered that, because of its
low thermal conductivity, even scaling of just a few
mm thick causes signifi cant overheating of the boiler
walls.
Pipe Connections
Connection of supply and return water connections
are located on the back of the boiler. The installation
of piping shall be in accordance with National, State
and local codes.
1. Pipe Connections
a) Supply and Return connections are 1" NPT.
See Figure 7. The pressure relief valve assem-
bly is factory installed in all natural draft
models.
b) The Gas connection is 1/2" NPT. See Figure
7.
c) Boiler drain ships installed from factory. See
Figure 1.
Figure 8
INTEGRAL DRAFT
HOOD
SUPPLY 1" NPT
GAS 1/2" NPT