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CGi
SERIES 4 — GAS-FIRED WATER BOILER —
4a
Water piping — general information
General piping information
If installation is to comply with ASME or Canadian requirements,
an additional
high temperature limit
supply piping between boiler and isolation valve. Set second control
to minimum 20°F above setpoint of first control. Maximum allowable
setpoint is 240°F. See Section
Use backflow check valve in cold water supply as required by local
codes.
Water temperature/LWCO sensor
A
is required when boiler is installed above
low water cutoff device
radiation level or by certain state or local codes or insurance com-
panies. The boiler has a pre-installed
Pressure/temperature gauge
Install pressure/temperature gauge in tee on supply piping (as shown
in drawing on page 3).
Isolation valves
Isolation valves are required to enable servicing of the boiler's
temperature sensor. Install as shown in appropriate piping diagram.
Relief valve
Install relief valve vertically in ¾" tapping on side of boiler. See
or
, page 21, and the tag attached to the relief valve for
Figure 16
17
manufacturer's instructions.
To avoid water damage or scalding due to relief
valve operation:
Discharge line must be connected to relief valve outlet and run
•
to a safe place of disposal. Terminate the discharge line to
eliminate possibility of severe burns should the valve discharge.
Discharge line must be as short as possible and be the same
•
size as the valve discharge connection throughout its entire
length.
•
Discharge line must pitch downward from the valve and termi-
nate at least 6" above the floor drain where any discharge will be
clearly visible.
The discharge line shall terminate plain, not threaded, with a
•
material serviceable for temperatures of 375°F or greater.
•
Do not pipe the discharge to any place where freezing could
occur.
•
No shutoff valve shall be installed between the relief valve and
boiler, or in the discharge line. Do not plug or place any obstruc-
tion in the discharge line.
•
Failure to comply with the above guidelines could result in fail-
ure of the relief valve to operate, resulting in possibility of severe
personal injury, death or substantial property damage.
•
Test the operation of the valve after filling and pressurizing
system by lifting the lever. Make sure the valve discharges freely.
If the valve fails to operate correctly, replace it with a new relief
valve.
20
Boiler Manual
maybe needed. Install control in
for wiring.
9b
water temperature/LWCO sensor
Circulator
The circulator is shipped loose (wiring pre-attached
to boiler) to allow you to locate it either in the re-
turn or supply piping, as desired. See page 3 for
a typical installation. Pipe the expansion tank to
the suction side of the circulator whenever pos-
sible. Install an air separator in the supply piping.
Connect the expansion tank to the air separator
only if the separator is on the suction side of the
circulator. Always install the system fill connection
at the same point as the expansion tank connec-
tion to the system.
Figures 16
near-boiler piping connections.
.
System water piping
See
(diaphragm-type or bladder-type ex-
Figure 16
pansion tank) or
Figure 17
tank) and
, for near-boiler and single-zone
Table 6
systems designed for return water at least 130°F.
See pages 22-23 to complete multiple-zone piping
or pages 24-29 to complete piping for radiant heat-
ing systems or converted gravity systems (large-
volume systems originally designed for circulation
by natural convection rather than a pump). See
page 29 for boilers used with refrigeration systems.
Table 6 Water pipe size (based on 20°F rise)
Boiler
model number
system
CGi-25
CGi-3, 4, 5
CGi-6, 7
CGi-8
Note: The boiler supply and return connections, the return/
drain tee and the supply/gauge tee supplied with
the boiler are 1¼" NPT. One of the circulator flanges
supplied with the boiler is 1¼". The other circulator
flange is the size of the recommended system piping
shown above.
Chillers or air handling units:
Install boiler such that —
•
Chilled medium, if used, is piped in parallel with
heating boiler. Use appropriate valves to prevent
chilled medium from entering boiler. Consult AHRI
Installation and Piping Guides.
•
If boiler is connected to heating coils located in
air handling units where they can be exposed to
refrigerated air, use flow control valves or other
automatic means to prevent gravity circulation
during cooling cycle. Circulation of cold water
through the boiler could result in damage to the
heat exchanger, causing possible severe person-
al injury, death or substantial property damage.
Part Number 550-142-302/0124
and
show typical
17
(closed-type expansion
To
From
system
¾"
¾"
1"
1"
1¼"
1¼"
1½"
1½"
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