Weil-McLain 4 Series Manual page 21

sTeam series
94
Figure 12 Multiple steam boiler piping — gravity condensate return
o r P 1 o r P 1
T o R 1 T o R 1
e i v e r e i v e r
T o r e c T o r e c
6 2 ¾ " 6 2 ¾ "
A Pipe as shown for gravity return systems, connecting
point A to the wet gravity return
For pumped-return systems, install boiler water level
control on each boiler with body mark at level indicated in
Figure 38, page 30 Provide one of the following at point A:
1 Separate feed pumps and check valves for each
boiler
2 Single feed pump, with separate solenoid valve for
each boiler
B For pumped-return systems, install a combination float
and thermostatic trap on each boiler to prevent flooding
of one boiler while other boiler is firing. Install trap in skim
tapping Connect traps to condensate receiver
Gravity-return systems are self-leveling if the wet
returns are piped to the common system wet return
C Install boiler piping as shown in the preceding pages of
this manual
550-100-157/0523
boiler manual
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E
E
D
C
R i s e r R i s e r
10
2 4 " m i n
1
9
l i n e l i n e
W a t e r W a t e r
8
4 "
B a c k B a c k
o f o f
b o i l e r b o i l e r
BOILER
RETURN
F
D
o r P 1 o r P 1
T o R 1 T o R 1
R i s e r R i s e r
1
e i v e r e i v e r
T o r e c T o r e c
9
W a t e r W a t e r
B a c k B a c k
o f o f
6 2 ¾ " 6 2 ¾ "
b o i l e r b o i l e r
BOILER
RETURN
B
A
D Install stop valves per ASME code requirements
For pump-return systems, if using automatic steam
valves, use only slow-opening automatic valves Use a
Weil-McLain Boiler Control System (such as a BCP panel)
to open each steam valve automatically before firing
burner
E Construct common supply drop header with pipe size at
least same size as largest boiler header size
F Use one of the following:
1 A Weil-McLain Boiler Control System (such as a BCP
panel) with header-mounted pressure control(s) to
sequence boilers, or
2 A steam pressure controller
G Install drip line in common supply drop header
• Gravity-return: Pipe drip line to wet return
• Pumped-return: Use combination float and
thermostatic trap and drain to condensate receiver
insTallaTion
s t e m
T o s y
C
e i v e r e i v e r
T o r e c T o r e c
10
2 4 " m i n
l i n e l i n e
8
4 "
B
1
2
3
G
4
5
A
6
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