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Part number 550-100-026/0404
GAS-FIRED WATER BOILER SERIES 2 — Boiler Manual
18
Chilled water systems
1. Install boiler so that chilled medium is piped in parallel with the heating
boiler. Use appropriate valves to prevent chilled medium from entering
boiler. See Figure 10 for typical installation of balancing valve and check
valve.
2. The space heating system may be zoned with circulators if a separate
circulator is supplied for the chilled water loop.
3. 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.
Follow these piping guidelines below to ensure chilled water
does not enter the boiler loop.
Chilled medium, if used, is piped in parallel with heating boiler
as shown in Figure 10. Use appropriate valves to prevent chilled
medium from entering boiler.
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.
Figure 10 Chilled water system plus optional
DHW piping
Legend Figure 10
Install water piping
(continued)
3
1 Ultra boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page 12 for piping details)
4 Relief valve discharge piping (see page 12 for details)
5 DHW circulator (see page 14 for suggested sizing)
6 Isolation valves
7 System circulator
9 Air separator (DO NOT use automatic air vents on systems fitted with closed-
type tanks)
10 Flow/check valves (with weighted seats to prevent gravity circulation)
11 Purge/drain valves
12 Boiler circulator
13 Zone valves, typical
15 Closed-type expansion tank
16 Water chiller
17 Check valve
18 Strainer
19 Balancing valve
20 Make-up water supply
21 Primary/secondary connection
NOTE 1: To ensure adequate flow rate through the boiler, use the following
pipe size on all boiler loop piping (connecting boiler to and from
the primary/secondary connection, item 21):
Ultra-80 or Ultra-105 – 1" or larger.
Ultra-155 or -230 – 1¼" or larger.
Ultra-310 – 1½" or larger.
Use at least the minimum piping size above and pipe the boiler
using only primary/secondary piping as shown. Failure to
follow these guidelines could result in system problems.