Weil-McLain CGA Series 2 Manual page 20

CGa Series 2 Gas-Fired Water Boiler — Boiler Manual
3d
Water piping — low temperature systems
Primary/secondary
Bypass piping method
Primary/secondary
the flow rate and temperature drop in the heating
circuit(s) is determined only by the heating circuit
circulator(s). So adjustment of the bypass valves in
the boiler circuit will not cause a change in the heating
circuit rate and temperature distribution.
Figures 13
arrangements using
(preferred) for low temperature systems such as
heating systems
alternatives, see pages 22 through 25.
The bypass valves (items
hot boiler outlet water with cooler system return water
— set to assure a minimum return water temperature
(at least 130°F) to the boiler. Set the valves as explained
below.
Temperature gauges
4a
Gauge
4b
Gauge
required
20
(preferred)
bypass piping is preferred because
14
and , page 21, show suggested bypass
primary/secondary
converted gravity systems
or
7a and 7b ) provide mixing of
is suggested, but optional on any system.
is optional on converted gravity systems, but
on radiant heating systems — to display the
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.
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.
water temperature being supplied to the radiant tubing.
8
Gauge
water temperature is accurately set for a minimum of
130°F. If this gauge is not available however, adjust the
valves such that the boiler-mounted temperature/pres-
sure gauge reads at least 150°F when the system return
water is cold (approximately 60°F water temperature).
Valve adjustment
(Figures 13 and 14 on ly)
bypass piping
radiant
1. Set the valves while the system is cool, setting for the
. For
coldest expected water temperature (usually 60°F
since the system will often drop to room tempera-
ture between cycles).
2. Start with valve
3. Gradually open valve
the temperature at gauge
4a
reads 60°F.
4. Note that valve
ter from the boiler supply which mixes with return
water. Valve
flowing through the boiler secondary loop.
system supply temperature
and the
).
system supply temperature
provide controls and piping
regardless of system supply temperature. Contact your
required
is on all systems to assure the return
7a fully closed and
7a
while closing valve
8
reads 130°F when gauge
7a
regulates the amount of hot wa-
7b
regulates the amount of system water
to the boiler could cause corrosion
regulating the boiler return
(such as provided by an
is relatively constant.
regulate the boiler return water
which can
to the boiler could cause corrosion
Part Number 550-142-900/0519
7b fully open.
7b
until
injec-
outdoor reset