4
PUMP #1
OFF
PUMP #1
ON
NORMAL BOILER
WATER LINE
(19mm)
3
/
4
"
DIFFERENTIAL
PUMP #2 ON
AT CAST LINE
7
/
8
"
DIFFERENTIAL
(22mm)
PUMP #2
ON
PUMP #2
OFF
PUMP #1
OFF
PUMP #2
ON
PUMP #2 ON
AT CAST LINE
NORMAL BOILER
WATER LINE
1
3
/
8
"
DIFFERENTIAL
(35mm)
Values are ±
8
" (3.2mm).
150 psi (10.5 kg/cm
2
) Levels
Approximate
Distance Above
Cast Line
Differential
Setting
In. (mm)
In. (mm)
Pump #1 Off
15
/
16
(24)
5
/
16
(8)
Pump #1 On
5
/
8
(16)
Pump #2 Off
5
/
8
(16)
3
/
8
(16)
Pump #2 On
1
/
4
(6.4)
Pump #1 Off
1
3
/
8
(41)
3
/
4
(19)
Pump #1 On
5
/
8
(16)
Pump #2 Off
7
/
8
(22)
7
/
8
(22)
Pump #2 On
0
(0)
Model 159S
0 psi
(0 kg/
cm
2
)
150 psi
(10.5 kg/
cm
2
)
Pressure
Settings and Differential Pressures (continued)
