Weil-McLain CGA Series 2 Manual page 22

CGa Series 2 Gas-Fired Water Boiler — Boiler Manual
3d
Water piping — low temperature systems
BOILER-bypass piping
method
This piping method (
boiler-bypass
a
bypassed around the boiler (through valve
method reduces the flow rate throughout the boiler, in
order to raise the average water temperature in the boiler
enough to prevent flue gas condensation. Boiler-bypass
piping is effective for some boilers — including the
CGa — provided the flow rates are adjusted according
to the instructions following.
Figures 15
converted gravity
for
systems) or
primary/secondary piping can't be applied. (
page 25, is another alternative, using system bypass in
place of boiler-bypass piping.
not suitable for radiant heating applications because it
does not protect the radiant system from possible high
water temperature.)
Boiler-bypass piping keeps system flow rate as high as
possible and temperature drop as low as possible, help-
ing to equalize the building heat distribution.
Temperature gauges
4a
Gauge
justed using cold (or room temperature) return water
22
Figure 15 16
or , page 23) is called
because part of the circulator flow is
16
and are alternative piping suggestions
(large water content or steam
radiant heating system
— for use when
Figure 17
is optional if the bypass valves will be ad-
Failure to prevent low return water temperature
of the boiler sections or burners, resulting in severe personal injury, death or substantial
property damage.
Radiant heating system piping should include a means of
water temperature
tion pumping control
Boiler return water temperature will be adequately controlled using the methods shown
in this manual provided the
DO NOT apply the methods of this manual if the system is equipped with an
control. provide controls and piping
Instead,
temperature at no less than 130°F
Weil-McLain representative for suggested piping and control methods.
prevent cold return water temperature
Failure to
damage to the sections or burners, resulting in possible severe personal injury, death or
substantial property damage.
to the boiler. (When setting the valves without gauge
4a
installed — using cold or room temperature water
— assume the return water temperature to be 60°F. Set
the valves so gauge
4b
Gauge is optional on converted gravity systems, but
7a ). This
required
on radiant heating systems — to display the
water temperature being supplied to the radiant tubing.
8 required
Gauge is
adjustment of the bypass valves. The boiler-mounted
temperature/pressure gauge can be used if a separate
temperature gauge is not installed.
Valve adjustment
1. Start with valve
Figure 17 ,
2. Gradually open valve
however, is
until the temperature at gauge
than gauge
through the boiler assures a low enough flow rate
and high enough average temperature to prevent
condensation even with low system return water
temperature.
7a
3. Valve
7b
regulates the boiler flow rate.
4. The boiler-mounted temperature/pressure gauge
may be used in place of a separate gauge
system supply temperature
and the
).
system supply temperature
which can
regardless of system supply temperature. Contact your
(continued)
8 reads at least 120°F.
on all systems to assure reliable
7a 7b
fully closed and
7a
while closing valve
8 reads 60 °F higher
4a
. A minimum 60°F temperature rise
regulates the system flow rate, while valve
to the boiler could cause corrosion
regulating the boiler return
(such as provided by an
is relatively constant.
outdoor reset
regulate the boiler return water
to the boiler could cause corrosion
Part Number 550-142-900/0519
fully open.
7b
8.
injec-