Weil-McLain SVF 1500 Manual page 15

SVF
™
Series 1
Commercial Condensing Gas-Fired Water Boiler — Boiler Manual
Install water piping
Recommended pipe sizing
DO NOT design the piping and components
given in Figure 10 without using one of the piping strate-
gies listed below. Insufficient flow will cause nuisance
outages due to limit operation. Excessive flow can damage
the boiler heat exchanger from erosion.
For systems with flow rates outside the range pro-
vided in Figure 10.
Higher flow rates:
Use Primary/Secondary piping (see pages 17, 18, 21, 22 & 23).
In a Variable/Primary flow system (see Figures 16, page 19 and
Figure 17, page 20), a differential pressure by-pass valve should
be added to by-pass the excessive flow, or provide an alternate
engineered solution.
Lower flow rates:
Use Primary/Secondary piping (see pages 17, 18, 21, 22 & 23).
In a Variable/Primary flow system (see Figures 16, page 19
and Figure 17, page 20), a flow switch is recommended
to be installed and set at the boilers minimum flow rate.
Figure 10
Flow rate and pressure drop data for
SVF 1500
Minimum
Water
GPM
Pressure
146
116
10
97
PSI
83
73
65
58
15
53
PSI 49
––
––
*
Suggested design flow rate (30°F temp. rise, water only)
SVF 1500/2000
** Notice: The control will reduce the firing rate when the temperature rise exceeds 60°F, at 68°F it will turn off the burner. For modulating
pumps a minimum flow rate of 49 gpm can be used, but the variable speed pump must be controlled to increase flow rate between minimum and full firing rate.
SVF 2500
Minimum
Water GPM
Pressure
242
194
10
162
PSI
139
121
108
97
15
88
75
PSI
––
––
* Suggested design flow rate (30°F temp. rise, water only)
**
Notice: The SVF 2500/3000 control will reduce the firing rate when the temperature rise exceeds 60°F, at 68°F it will turn off the burner. For modulating
pumps a minimum flow rate of 75 gpm can be used, but the variable speed pump must be controlled to increase flow rate between minimum and full firing rate.
Part number 550-100-250/0819
(continued)
the ranges
TM
SVF
boilers
100% Rate
Boiler head
loss
Temperature
(Feet w.c.)
Rise (°F)
20 3.0
25 2.2
*30 1.7
35 1.4
40 1.1
45 1.0
50 0.8
55 0.7
60 0.6
–– ––
–– ––
100% Rate
Boiler head
loss
Temperature
(Feet w.c.)
Rise (°F)
20 7.4
25 5.3
*30 4.1
35 3.3
40 2.7
45 2.3
50 1.9
55 1.7
1.3
**65
–– ––
–– ––
This will prevent the boiler from firing with a flow rate that is
too low. Once the system load increases the resultant higher
water flow will make the flow switch.
Figure 9
Boiler head loss vs flow rate for
10
9
8
7
6
5
4
3
2
1
0
30 60 90 120
Flow Rate (GPM)
SVF 2000
Minimum
Water
GPM
Pressure
190
152
10
127
PSI
109
95
84
76
15
69
PSI 63
54
51
SVF 3000
Minimum
Water GPM
Pressure
285
228
10
190
PSI
163
143
127
114
15
104
PSI 95
81
76
TM
SVF
boilers
SVF 2500/3000
SVF 1500/2000
150 180 210 240 270
100% Rate
Boiler head
loss
Temperature
(Feet w.c.)
Rise (°F)
20 4.4
25 3.2
*30 2.5
35 2.0
40 1.6
45 1.4
50 1.2
55 1.0
60 0.9
** 70 0.7
75 0.7
**
100% Rate
Boiler head
loss
Temperature
(Feet w.c.)
Rise (°F)
20 9.3
25 6.7
*30 5.2
35 4.1
40 3.4
45 2.9
50 2.5
55 2.1
60 1.9
** 70 1.5
** 75 1.4
300
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