Closed-System Design - Danfoss PAHT 2 Operation, Installation, And Maintenance Manual

Operating guide
34 | 180R9287_AQ073186503097en-001004
PAHT 2-12.5 pumps
7.4 Closed-system design (not applicable
for PAHT 256-308)
A Inlet line:
Dimension the inlet line to obtain mini-
mum pressure loss (large ow, minimum
pipe length, minimum number of bends/
connections, ttings with small pressure
losses and restrictions).
B Inlet lter:
Install the lter (1) in front of the tank (2).
Please consult the Danfoss lter data sheet
for guidance on how to select the right
lter.
C Monitoring pressure switch:
Install the monitoring pressure switch (3) in
front of the lter (1). Set the maximum inlet
pressure to 2 barg (29.0 psig). The monitor-
ing pressure switch will stop the pump (5) if
inlet pressure is higher than 2 barg (29.0
psig), indicating that the lter element
must be changed.
D Monitoring temperature switch:
Install the monitoring temperature switch
(4) in the tank. Set the temperature value
according to technical data, item 4. The
monitoring temperature stops the pump if
inlet temperature is higher than the set
value.
11
Reservoir
E
F
G
H
I
J
2
4
6
PI
1
3
Hoses:
Always use exible hoses (6) to minimize
vibrations and noise.
Inlet pressure:
In order to eliminate the risk of cavitation
and other pump damage, pump inlet
pressure must be maintained according to
speci cations described in item 4, technical
data.
Non-return valve (7):
Should be installed after the outlet to
prevent pump backspin, which may ruin
the pump.
Pressure relief valve:
As the Danfoss PAHT pump begins to
create pressure and ow immediately after
start-up regardless of any counter pressure,
a pressure relief valve (8) should be
installed to prevent system damage.
System water lling:
To ensure proper ltration of new water
(10) supplied to the system, always use the
lling valve (9).
Minimum level switch:
Install the minimum level switch (11) above
the outlet of the reservoir. The level switch
must stop the pump if the water in the
reservoir is below the switch, which
indicates that the reservoir is empty.
5
6 7
PI
9
8
10
© Danfoss | 2023.09
System