Specifications

Part number 550-100-090/0809
g a s -f i r e d w a t e r b o i l e r — Boiler Manual
12
Legend — Figure 5
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
20 Make-up water supply
21 Primary/secondary connection
23 DHW connections — see water heater manual for piping
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
Install water piping — typical systems
Figure 5 Zone valve zoning plus optional DHW piping
Zoning with zone valves
Connect boiler to system as shown in 1. Figure 5 when zone valve
zoning. The primary/secondary piping shown ensures the boiler
loop will have sufficient flow. It also avoids applying the high head
of the boiler circulator to the zone valves. Also see the information
on page 14 and page 15 for suggested piping and sizing.
Use at least the MINIMUM pipe size shown in Figure 5
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.
When using a closed-type expansion tank, connect the expansion 2.
tank and make-up water piping as shown in Figure 4, page 11. (DO
NOT use a closed-type tank with a PLUS water heater.)
Connect DHW (domestic hot water) piping to indirect storage 3.
water heater as shown.
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 circulators4.
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 and system circulator
as Circulator 3. See Field wiring instructions, beginning on
page 26, for details.
Other piping alternatives
See page 14 and page 15 and ADVANCED INSTALLATION section for additional piping suggestions.
MINIMUM
Boiler loop pipe size
Ultra-80, 105
Ultra-155, 230
Ultra-299, 399
1”
1¼”
1½”
See CAUTION at left.