Grundfos Fire NKF, Installation And Operating Instructions Manual

Page: 20 / 388

English (GB)
20
10.7 Priming tank and test pipe
If the pump set is supplied from a storage tank and the suction
height is negative, a pump priming tank must be installed on the
suction side in accordance with local regulations. See also the
standard applying to the pump set.
Install a test pipe running from the discharge pipe to the storage
tank. The discharge pipe and the test pipe must be fitted with
isolating valves.
If the pump set is fed directly from the public water supply, the
test pipe must have a free outlet according to the standard
applying to the pump set.
10.8 Bypass pipe
Pumps with electric motor must be equipped with a bypass pipe
from the discharge side of the pump (before the isolating valve) to
a tank or a free outlet to ensure that the pump will not be running
against a closed valve. See section
9.4 Minimum flow rate
.
The vent hole of the pump housing can be used for connecting
the bypass pipe. In this case, the discharge pipe must have a port
for venting.
10.9 Connecting the cooling system
Water-cooled diesel engines are cooled by a flow of water
through a pipe connected to the heat exchanger via a cooling
circuit.
The cooling circuit consists of the pipe system, a stopcock (A),
a diaphragm valve (B) and a pressure gauge (C). See fig. 21.
Fig. 21
Cooling circuit
Fit a hose on the discharge side of the heat exchanger.
See fig. 22. The other end of the hose must be a visible free
outlet. The nominal hose diameter must not be smaller than the
outlet of the heat exchanger (whether it is a 1" or 1 1/4" version).
Fig. 22
Outlet of the heat exchanger
In addition to the suction pipe of the pump, the copper pipe
connected to the diaphragm valve must be connected to the
suction pipe. See fig. 23. The suction pipe must therefore have a
connection port (1/2").
The plug to be used for connecting the copper pipe is attached to
the fuel pipe upon delivery. See fig. 24. The copper pipe prevents
water from escaping from the storage tank through the pump and
the heat exchanger when the filling level in the storage tank is
above the open discharge of the heat exchanger. The pressure
on the suction side will ensure that the diaphragm valve closes
(fig. 21, pos. B).
Fig. 23
Installation of copper pipe
The stopcock (fig. 21, pos. A) is closed during normal operation.
It should only be opened if the diaphragm valve is faulty and
remains in closed position. A diaphragm valve blocked in closed
position is indicated by a lack of pressure on the pressure gauge
(fig. 21, pos. C).
Fig. 24
Plug for additional pipe
Note
This section applies to pump sets with water-
cooled diesel engine.
T
M
0
4
0
113
50
07
Note
The design of the cooling circuit depends on the
type of pump set.
TM
04 98
48 021
1
A
B
C
Additional
pipe
TM
05 19
77 41
11
TM
04 984
9 021
1
Copper pipe