Suction Pipe; Discharge Piping - Grundfos CR Series Installation And Operation Manual

Figure 1: Bolt Hole Centers
CR(I)(N) 1s, 1, 3, 5 & CRT 2, 4
11
8 / (220mm) Max
16"
7 1 / (180mm)
16"
(4) 1 / " HOLES
2
(13mm)
CR(I)(N) 10, 15, 20 & CR(N)(X)(T) 8, 16
10 1/16 (256mm) Max.
"
1
8 / (215mm)
2"
(4) 1 / " HOLES
2
(13mm)
CR(N) 32
3
11 / (298mm)
4"
7
9 / (240mm)
16"
(4) / " HOLES
9
16
(14mm)
CR(N) 45, 64
13" (331mm)
1
10 / (266mm)
2"
(4) 9 / " HOLES
16
(14mm)
CR(N) 90
3
13 / (348mm)
4"
11" (280mm)
(4) 9 / " HOLES
16
(14mm)
Pipework
NOTE: The CR(N) pumps are shipped with covered suction and discharge. The covers
must be removed before the final pipe flange to pump connections are made.

Suction pipe

The suction pipe should be adequately sized and run as straight and short as possible to keep friction losses to
a minimum (minimum of four pipe diameters straight run prior to the suction flange). Avoid using
unnecessary fittings, valves or accessory items. Butterfly or gate valves should only be used in the suction line
when it is necessary to isolate a pump because of a flooded suction condition. This would occur if the water
source is above the pump. See Figures 2 and 3. Flush piping prior to pump installation to remove loose debris.
Flooded Suction
Figure 2
Minimum suction pipe sizes
The following recommended suction pipe sizes are the smallest sizes which should be used with any
specific CR pump type. The suction pipe size should be verified with each installation to ensure good pipe
practices are being observed and excess friction losses are not encountered. High temperatures may
require larger diameter pipes to reduce friction and improve NPHSA.
CR(I)(N) 1s, 1, 3, CRT 2
CR(I)(N) 5, CRT 4
CR(I)(N)(X) 10, 15, 20, 8, 16
CR(N) 32
CR(N) 45
CR(N) 64
CR(N) 90

Discharge piping

It is suggested that a check valve and isolation valve be installed in the discharge pipe. Pipe, valves and
fittings should be at least the same diameter as the discharge pipe or sized in accordance with good piping
practices to reduce excessive fluid velocities and pipe friction losses. Pipe, valves and fittings must have a
pressure rating equal to or greater than the maximum system pressure. Before the pump is installed it is
recommended that the discharge piping be pressure checked to at least the maximum pressure the pump is
capable of generating or as required by codes or local regulations.
Whenever possible, avoid high pressure loss fittings, such as elbows or branch tees directly on either side of
the pump. The piping should be adequately supported to reduce thermal and mechanical stresses on the
pump. Good installation practice recommends the system be thoroughly cleaned and flushed of all foreign
materials and sediment prior to pump installation. Furthermore, the pump should never be installed at the
lowest point of the system due to the natural accumulation of dirt and sediment. If there is excessive
sediment or suspended particles present, it is advised a strainer or filter be used. Grundfos recommends
that pressure gauges be installed on inlet and discharge flanges or in pipes to check pump and system
performance.
NOTE: To avoid problems with waterhammer, fast closing valves must not be used in
CRN-SF applications.
Suction Lift*
Figure 3
* CRN-SF pumps cannot be used for suction lift. The suction
pipe should have a fitting on it for priming.
1" Nominal diameter sch 40 pipe
1 1/4" Nominal diameter sch 40 pipe
2" Nominal diameter sch 40 pipe
2 1/2" Nominal diameter sch 40 pipe
3" Nominal diameter sch 40 pipe
4" Nominal diameter sch 40 pipe
4" Nominal diameter sch 40 pipe
5