Part Number 550-141-186/0100
17
• Installation • Start-Up • Maintenance • Parts
Primary/secondary
piping
(systems above 140°F)
Weil-McLain recommends piping
as shown in
Figure 15
. For single
boilers, pipe as shown for one unit.
Size secondary boiler pump GPM
for 20°F to 40°F temperature rise
through boiler. Secondary boiler
pump head will be very low.
Calculate only secondary piping
circuit resistance. Boiler resistance
will not exceed 6" w.c.
Primary pump GPM and head
calculation should not include
secondary boiler circuits. Primary
pump can operate continuously
during heating season.
Distance 12" or less.
Flow/check valve.
Hand valve.
Expansion tank(s), relief valves and
other accessories are required but
not shown.
Refrigeration system
piping
The boiler must be installed so that
chilled medium is piped in parallel
with the heating boiler with
appropriate valves to prevent the
chilled medium from entering the
boiler. See
Figure 16
. Consult
I=B=R Installation and Piping
Guides.
If boiler is connected to heating
coils located in air handling units
where they can be exposed to
refrigerated air, gravity circulation
during cooling cycle must be
prevented with flow control valves
or other automatic means.
1
2
3
4
5
6
Figure 15
Figure 16
Diaphragm
expansion
tank (if used)
12 " maximum
Flow/check
valve
Flow/check
valve
2
1
1
4
4
5
5
5
5
3
186-15
Water
chiller
Expansion tank
Circulator
Check
valve
Strainer
Boiler
Shut-off
valve
System
supply
System
return
Balancing
valve
186-16
