Weil-McLain CGi 4 Series Manual page 28

CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4d
Piping — low temperature systems
SYSTEM-bypass piping
method
This piping method is called a
part of the circulator flow bypasses the system (through
valve ). This bypassed hot water from the boiler outlet
7a
mixes with cooler system return water temperature in
order to provide minimum 130°F return water to the
boiler. Valve
need to be slightly closed on some low pressure drop
systems in order to cause enough flow through valve
Figure 24
return water temperature control for boilers installed
on
converted gravity systems
steam systems).
apply the piping of
Do not
ing systems
temperature provided to the system and could result in
excessive water temperature in the radiant tubing.
System-bypass piping as shown in
with either zone valve or circulator zoning. When used
with circulator zoning however, the boiler circulator
(item ), must be piped as shown. It cannot be used as
3
one of the zoning circulators.
28
system-bypass
will most often be full open, but may
7b
is an alternative piping method that provides
(large water content or
on
Figure 24
. It provides no method regulating the water
Figure 24
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
Do not apply system-bypass piping if the reduced flow
in the system could cause poor heat distribution. That
is, system-bypass piping reduces the flow in the system
and increases the water temperature supplied to the
because
system. This can cause increased heat from radiators
at the beginning of the system and reduced heat from
radiators near the end of the system.
Valve adjustment
.
7a
1. Start with valve
2. Gradually open valve
the temperature at gauge
times.
radiant heat-
3. Valve
7a
mixed with return water. Valve
drop in the system needed to balance flow through
valve 7a
can be used
4. The valve adjustment should be done with the
system at the coldest expected temperature (60°F
for converted gravity systems or high mass radiant
systems).
and the
system supply temperature
).
system supply temperature
provide controls and piping
at
no less than 130°F
(continued)
fully closed and
7a 7b
while closing valve
7a
reads at least 130°F at all
8
regulates the amount of boiler supply water
causes a pressure
7b
and the system.
to the boiler could cause corrosion
regulating the boiler return
(such as provided by an
is
relatively constant.
which can
regulate the boiler re-
regardless of system supply temperature.
to the boiler could cause corrosion
Part Number 550-142-302/0520
fully open.
until
7b
injec-
outdoor