Specifications

Part number 550-100-090/0809
51
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
ADVANCED INSTALLATION
Legend — Figure 51
1 Ultra boiler
2 Indirect water heater (DHW), if used
3 Boiler relief valve (see page 9 for piping details)
4 Relief valve discharge piping (see page 9 for details)
5 DHW circulator (see page 52 for suggested sizing)
6 Isolation valves
7 System circulator (see information above for wiring)
8 Diaphragm (or bladder) type expansion tank (see page 52 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
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 (tees no more than 12 inches apart)
23 DHW supply/return
24 Strap system supply and return sensors to lines as shown, at least 6 pipe
diameters (but no more than 3 feet) from boiler connection tees.
25 Systems using high-head pumps may require a bypass pressure regulator
to prevent damage to control valves.
Items supplied with boiler
Items supplied by others
Chilled water systems
Install boiler so that chilled medium is piped in parallel with the 1.
heating boiler. Use appropriate valves to prevent chilled medium
from entering boiler. See Figure 51 for typical installation of bal-
ancing valve and check valve.
Use at least the MINIMUM pipe size shown in Figure 51
on all boiler loop piping (connecting boiler to and from
the primary/secondary connection, item 21). Use only
primary/secondary piping as shown.
Failure to fol-
low these guidelines could result in system problems.
The space heating system may be zoned with circulators if a separate 2.
circulator is supplied for the chilled water loop.
If antifreeze is used in the system, consider the effects of
antifreeze on circulator sizing and DHW performance.
Some local codes may require double-wall DHW heat
exchanger design.
Chilled medium, if used, is piped in parallel with heating
boiler as shown in Figure 51. Use appropriate valves to
prevent chilled medium from entering boiler.
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.
By default, the U-Control Module turns off space heating
during DHW heating (if DHW input is priority 1). The
boiler circulator will turn off, preventing hot water from
circulating to the system (optional timeout setting can
be used to override). The flow/check valve shown on the
boiler outlet piping prevents gravity circulation in the
boiler loop during DHW heating.
Controlling the circulators3.
The U-Control can control up to three circulators (boiler cir-a.
culator and two others). Refer to Field wiring, beginning on
page 26, for instructions on wiring to circulators.
The factory default settings are: DHW circulator as Circula-b.
tor 1, boiler circulator as Circulator 2. See Field wiring instruc-
tions, beginning on page 26, for details.
Figure 51 Chilled water system plus optional DHW
piping
Install water piping — advanced (continued)
MINIMUM
Boiler loop pipe size
Ultra-80, 105
Ultra-155, 230
Ultra-299, 399
1”
1¼”
1½”
See CAUTION at left.