Part number 550-100-090/0809
gas
-
fired
water
boiler
—
Boiler Manual
14
Using with Weil-McLain PLUS water heaters
PLUS DHW installation — quick-selection
The information in this section is for usage of Ultra boilers
with Weil-McLain PLUS indirect water heaters.
For dedicated DHW applications, use the circulator supplied
with the boiler to circulate to the water heater as shown in
this section.
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 over-
ride).
DO NOT use a closed-type expansion tank on a system with
a Weil-McLain PLUS water heater. The water heater must use
an automatic air vent. Operation of the automatic air vent
will deplete air in the piping, causing the expansion tank to
waterlog. Always use a diaphragm- or bladder-type expansion
tank with PLUS water heaters.
Follow the guidelines on this page and
1.
page 15 to connect the water
heater to the boiler. Use Figure 8 for dedicated water heating-only
applications. Use Figure 9 and Figure 10, page 15 for combined space
heating/water heating applications.
See ADVANCED INSTALLATION section for additional piping information and applications.
Use the table below to size DHW loop piping and select a circulator (see ADVANCED section for other DHW tanks)
Figure 7
Boiler
Ultra-
Partial load (see Figure 9 and Figure 10, page 15)
(combined space heating/water heating application)
Dedicated boiler (see Figure 8)
(water heating only)
PLUS
model
GPM
MBH
115/140
GPH
115/140
Head
loss (ft)
DHW
pipe size
CIRC
PLUS
model
GPM
MBH
115/140
GPH
115/140
Head
loss (ft)
DHW
pipe size
CIRC
80
(71 MBH)
40
6.5
71/71
160/124
8.5
1
007
40
6.5
71/71
160/124
8.5
1
007
60
6.5
71/71
168/132
8.5
1
007
60
6.5
71/71
168/132
8.5
1
007
80
6.5
71/71
176/140
8.5
1
007
80
6.5
71/71
176/140
8.5
1
007
105
(94 MBH)
40
10.1
94/94
217/154
17.0
1¼
0014
40
6.4
94/86
203/141
8.6
1
007
60
6.4
94/94
211/162
8.6
1
007
60
6.4
94/94
211/162
8.6
1
007
80
6.4
94/94
219/170
8.6
1
007
80
6.4
94/94
219/170
8.6
1
007
155
(139 MBH)
40
12.1
119/98 248/160
15.9
1¼
0014
40
12.1
119/98 248/160
15.9
1¼
0014
60
12.1 139/120 295/220
15.9
1¼
0014
60
12.1 139/120 295/220
15.9
1¼
0014
80
12.1 139/139 305/230
15.9
1¼
0014
80
12.1 139/139 305/230
15.9
1¼
0014
230
(207 MBH)
40
13.5 120/100 251/162
15.2
1¼
0014
40
Not recommended — boiler capacity
exceeds maximum output of water heater
60
18.4 169/128 350/207
23.7
1½
1400-20
60
80
13.5 207/207 430/325
15.2
1¼
0014
80
13.5 207/207 430/325
15.2
1¼
0014
299
(252 MBH)
40
13.1 120/100 250/162
9.7
1¼
0010
40
Not recommended —
boiler capacity exceeds
maximum output of water heater
60
19.3 170/129 351/208
11.7
1½
0014
60
80
24.9 252/252 510/381
18.4
1½
1400-20
80
399
(365 MBH)
40
13.1 120/100 250/162
9.7
1¼
0010
40
60
19.3 170/129 351/208
11.7
1½
0014
60
80
24.9 320/253 636/382
18.4
1½
1400-20
80
Ultra boiler with Ultra PLUS or PLUS
Figure 8
water heater — dedicated water heating
application, typical piping schematic
The PLUS water heater can also be installed as one
2.
of the zones in the system. This method, however,
requires flow through the main system even during
the summer (non-space heating) months. Piping
as shown in Figure 9 and Figure 10, page 15 allows
isolation of flow to just the water heater piping
during non-heating periods.