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Part number 550-100-026/0404
GAS-FIRED WATER BOILER SERIES 2 — Boiler Manual
16
Install water piping
(continued)
3
Figure 8 Circulator zoning plus optional
DHW piping
Zoning with circulators
1. Connect boiler to system as shown in Figure 8 when
circulator zoning. The boiler circulator cannot be used
for a zone. It must supply only the boiler loop.
2. Install a separate circulator for each zone.
3. When using a closed-type expansion tank, connect
the expansion tank and make-up water piping as
shown in Figure 4, page 13.
4. Connect DHW (domestic hot water) piping to indirect
storage water heater as shown.
The PhD Control Module turns off
space heating during DHW heating. The
boiler circulator will turn off, preventing
hot water from circulating to the system.
The flow/check valve shown on the boiler
outlet piping prevents gravity circulation
in the boiler loop during DHW heating.
Legend Figure 8
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
8 Diaphragm (or bladder) type expansion tank (see page 12
for piping of closed-type expansion tank, if used)
9 Air separator [with automatic air vent only on systems
using diaphragm (or bladder) type expansion tank]
10 Flow/check valves (with weighted seats to prevent gravity
circulation)
11 Purge/drain valves
12 Boiler circulator
14 Zone circulators, typical
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.