Weil-McLain CGi Series 3 Installation And Maintenance Manual page 29

CG i
GAS-FIRED wATER BOILER- sERIEs a -
Boiler Manual
4d
Piping - low temperature systems
<conlinued)
From system
8
To system
Aft~~~~
t:lrcu/4tor
locstlon
II
Figure 24 System-bypass piping - Zoning with
zone valve
or
circulators, return water
130"F
or
higher - (Aitematlve to boiler-
bypass piping Figures 22 and 23)
3 System or zone circulator
7 System temperature valves (see instructions to the
left for adjusting valves)
8 Blend temperature gauge
9 Relief valve
10 Automatic air vent (with
diaphra~m-type
expan-
sion tank), or connect to tank fittmg (closed-type
expansion tank). DO NOT use an automatic air vent
when using dosed-type expansion tank. It would
allow air to leave the system, causing waterlogging
of the expansion tank.
11 Fill valve
12 Diaphragm-type or bladder-type expansion tank,
if used (For d osed-type expansion tank, pipe fro m
top of air separator to tank fitting as in
Rgure
17,
page 21.)
4e
Water piping- refrigeration system
Figure 25 Piping refrigeration systems
System
:I
I
Expansion tank
supply
I
-
- -T •
t
Shut- off
Circulator
(-<
valve
Water
chiller
t
; Strainer
Cheek
Boiler
B:l
•
valve
II
System t
return
-
-
Balancing
) 1(1»
valve
Part
Number 550-142-780/0712
Prevent chilled water from
entering boiler
Install boiler so that chilled medium is piped in parallel
with the heating boiler. Use appropriate valves to prevent
chilled medimn from entering boiler. See Figure 18 for
typical installatio n of balancing valve and check valve.
If boiler is connected to heating coils located in air han-
dling units where they can
be
exposed to refrigerated
air, use flow control valves or other automatic means to
prevent gravity circulation during cooling cycle.
29