Install Instructions

T (°F)
Flow (GPM)
HEAD
(ft. w.c.)
Model 70 (70,000 Btu/hr)
20 6.5 3.6
30 4.3 2.0
40 3.3 1.3
Model 110 (110,000 Btu/hr)
20 10.1 7.1
30 6.7 3.8
40 5.1 2.5
Model 155 (155,000 Btu/hr)
20 14.3 6.1
30 9.5 2.7
40 7.2 1.5
System water piping methods
Near boiler piping
1. Connect boiler to system only as shown in
Figure 49, page 45 and Figure 50, page 46 . The
primary/secondary piping shown ensures the boiler
loop will have suffi cient fl ow.
2. Select a boiler loop temperature rise from
Figure 51 . The table indicates the fl ow and head
loss characteristics at that temperature rise.
Verify that the boiler loop piping
matches closely with the listed criteria in the
NOTICE below. If near boiler piping is different,
calculate head loss separately using heat exchanger
pressure drop information from Figure 46, page 42
and match to an the included circulator.
The pressure drops shown are for
near boiler piping as illustrated in
Figure 49, page 45 and Figure 50, page 46
with 20 feet of straight piping.
Figure 51 Estimated head loss of boiler
loop piping and recommended
circulators.
Figure 52 Estimated head loss of boiler loop piping and
recommended circulators.
8
7
6
5
4
3
2
1
0
0 2 4 6 8 10 12 14 16
155
70/110
70/110 Models
155 Model
Flow Through Heat Exchanger and Near-Boiler Piping (GPM)
Pressure Drop (ft. w.c.)
Part number 550-100-191/0917
47
®
gas-fired water boiler — 70/110/155 Boiler Manual
Primary/Secondary System Piping - Single Boiler System (continued)
See Advanced Manual for Multiple Boiler Systems