Weil-McLain CGi 4 Series Manual page 24

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4d
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 20 and 21
using
primary/secondary
for low temperature systems such as
systems
tives, see pages 26 through 29.
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
Gauge
4a
Gauge
4b
but
required
24
(preferred)
bypass piping is preferred because
show suggested bypass arrangements
bypass piping (preferred)
radiant heating
or
converted gravity systems
and ) provide mixing of
7a 7b
is suggested, but optional on any system.
is optional on converted gravity systems,
on radiant heating systems — to display
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
apply the methods of this manual if the system is equipped with an
DO NOT
Instead,
reset control.
turn water temperature
Contact your Weil-McLain representative for suggested piping and control methods.
Failure to
prevent cold return water temperature
damage to the sections or burners, resulting in possible severe personal injury, death or
substantial property damage.
Boiler Manual
the water temperature being supplied to the radiant
tubing.
Gauge 8 is required
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 20 and 21 only)
1. Set the valves while the system is cool, setting for the
. For alterna-
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
reads 60°F.
4a
4. Note that valve
ter from the boiler supply which mixes with return
water. Valve
flowing through the boiler secondary loop.
and the
system supply temperature
).
system supply temperature
provide controls and piping
at regardless of system supply temperature.
no less than 130°F
on all systems to assure the return
fully closed and fully open.
7a 7b
while closing valve
7a
reads 130°F when gauge
8
regulates the amount of hot wa-
7a
regulates the amount of system water
7b
to the boiler could cause corrosion
regulating the boiler return
(such as provided by an
is
relatively constant.
outdoor
which can
regulate the boiler re-
to the boiler could cause corrosion
Part Number 550-142-302/0520
until
7b
injec-