Open-System Design - Danfoss PAHT Operation, Installation, And Maintenance Manual

Operation guide
34 | 180R9288_AQ109686503100en-001301
Installation, Operation and Maintenance Manual for PAHT 20-90 pumps
7.3

Open-system design

A Inlet line:
Dimension the inlet line to obtain
minimum pressure loss (large flow,
minimum pipe length, minimum
number of bends/connections,
fittings with small pressure losses and
restrictions).
B Inlet filter:
Install the inlet filter (1) in front of the
PAHT pump (2). Please consult the
Danfoss filter data sheet for guidance
on how to select the right filter.
C Monitoring pressure switch:
Install the monitoring pressure switch
(3) between the filter and the pump
inlet. Set the minimum inlet pressure
according to specifications described in
item 4, technical data. The monitoring
pressure switch stops the pump if inlet
pressure is lower than the set minimum
pressure.
D Monitoring temperature switch:
Install the monitoring temperature
switch (4) between the filter and the
pump, on either side of the monitoring
pressure switch. Set the temperature
value according to technical data, item
4. The monitoring temperature switch
stops the pump if inlet temperature is
higher than the set value.
1
8
E
F
G
H
Note: If a non-return valve is mounted in the
inlet line, a low-pressure relief valve is also
recommended between the non-return valve (8)
and the pump to protect against high-pressure
peaks.
4 5
PI
3
Hoses:
Always use flexible hoses (5) 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 specifications
described in item 4, technical data.
Non-return valve (6):
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 flow immediately
after start-up regardless of any counter
pressure, a pressure relief valve (7)
should be installed to prevent system
damage.
2 5 6
PI
SYSTEM
7
© Danfoss | 2023.12