Instruction
PAH, PAHT pumps
PAH / PAHT 2-12.5
Instruction
PAH / PAHT / PAHT G 2-6.3 pumps/
PAH / PAHT / PAHT G 10-12.5 pumps
danfoss.high-pressurepumps.com
hpp.danfoss.com
Instruction Pump instruction PAH / PAHT 2-12.5
Table of Contents 1. Identication ...........................................................................2
2. System design ..........................................................................3
2.1 Closed-system design ..................................................................3
2.2 Open-system design ....................................................................4
2.3 General guidelines for calculation of pressure losses .....................................5
2.4 General comments on...................................................................5
3. Building up the pump unit ..............................................................6
3.1 Mounting...............................................................................6
3.2 Direction of rotation ....................................................................6
3.3 Orientation .............................................................................6
3.4 Protection from too high pressures ......................................................7
3.5 Connections ............................................................................7
4. Initial start-up ...........................................................................8
5. Operation...............................................................................8
5.1 Water quality ...........................................................................8
5.2 Temperature............................................................................8
5.3 Pressure ................................................................................8
5.4 Dry running.............................................................................8
5.5 Disconnection ..........................................................................8
5.6 Storage .................................................................................8
5.6.1 Water hydraulic systems, water recirculated..............................................8
5.6.2 Open-ended systems with water supply from tank. ......................................9
5.6.3 Open-ended systems with direct water supply. ..........................................9
1. Identication
6 Service..................................................................................9
7. Recommended service intervals.........................................................9
7.1 General information.....................................................................9
7.2 Inspection of pump parts ...............................................................9
7.3 How to inspect the pump ...............................................................9
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180R9277 | AN103586502885en-000501
© Danfoss | DHS (im) | 2020.08
Instruction Pump instruction PAH / PAHT 2-12.5
PI
System
PI
M
1
2
3
4
5 5
7
6
2. System design 2.1 Closed-system design
A Inlet line:
Dimension the inlet line to obtain minimum pressure loss (large ow, minimum
pipe length, minimum number of bends/
connections, and ttings with small
pressure losses).
B Inlet lter:
Install the inlet 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 monitoring 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.
E Hoses:
Always use exible hoses (6) to minimize
vibrations and noise.
11
F Inlet pressure:
In order to eliminate the risk of cavitation
and other pump damage, pump inlet
pressure must be maintained according to
specications described in item 4, technical
data.
G Non-return valve (7):
Should be installed after the outlet to
prevent pump backspin, which may ruin
the pump.
H 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.
I System water lling:
To ensure proper ltration of new water
(10) supplied to the system, always use the
lling valve (9).
J 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.
2
4
Reservoir
6 6 7
PI
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M
PI
System
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© Danfoss | DHS (im) | 2020.08
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Instruction Pump instruction PAH / PAHT 2-12.5
2.2 Open-system design
A Inlet line:
Dimension the inlet line to obtain minimum pressure loss (large ow, minimum
pipe length, minimum number of bends/
connections, and ttings with small
pressure losses).
B Inlet lter:
Install the inlet lter (1) in front of the PAHT
pump (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)
between the lter and the pump inlet. Set
the minimum inlet pressure according to
specications 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 lter 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.
E Hoses:
Always use exible hoses (5) to minimize
vibrations and noise.
F Inlet pressure:
In order to eliminate the risk of cavitation
and other pump damage, pump inlet
pressure must be maintained according to
specications described in item 4, technical
data.
G Non-return valve (6):
Should be installed after the outlet to
prevent pump backspin, which may ruin
the pump.
H 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 (7) should be
installed to prevent system damage.
Note: If a non-return valve is mounted in the
inlet line, a low-pressure relief valve is also
required between the non-return valve (8) and
the pump to protect against high-pressure
peaks.
1 4 5 5 6
PI
8
M
2
PI
SYSTEM
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180R9277 | AN103586502885en-000501
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Instruction Pump instruction PAH / PAHT 2-12.5
2.3 General guidelines for calculation of
pressure losses
The suction conditions can be optimized
according to below guidelines.
In smooth pipes and hoses
In 90° bends
© Danfoss | DHS (im) | 2020.08
2.4 General comments on
Filtration
A good ltration is vital to ensure a long and
trouble free life of the pump.
When selecting a lter or strainer, please note
that lter materials should be compatible with
water, i.e. should neither corrode or dissolve. Also
be aware of the electrochemical series of the
applied materials.
• Main lter must have a neness of 10 µm
abs. β
≥ 5,000.
• The pressure loss across the lter should be
10
monitored.
• Please contact the Danfoss Sales Organization for further lter details.
Water tank
Must be made of corrosion-proof material such
as stainless steel or plastic and must be sealed to
prevent entrance of impurities from the environment.
Automatic pressure equalization between tank
and surroundings must be ensured.
Inlet from the water supply (the return line) and
inlet to the pump should be placed in opposite
ends of the tank to calm and deaerate the water,
and to ensure optimum opportunity for particles
to settle.
Pump suction line should be placed above the
tank bottom in order to prevent settled particles
from being led into the pump.
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Instruction Pump instruction PAH / PAHT 2-12.5
unit
We recommend a separation (“wall”) to separate
the inlet from the outlet end of the tank.
3.1 Mounting3. Building up the pump
Monitoring
It is recommended to continuously monitor the
following conditions:
• Water level in the tank
• Filter contamination
• Pressure (inlet- and outlet side of the
pump)
A: Elastic coupling
B: Bell housing
C: Motor shaft
If alternative mounting is desired, please contact
the Danfoss Sales Organization.
Choose proper tolerances to ensure an easy
mounting of the elastic coupling without use of
tools.
Please take care to observe the recommended
length tolerances of the chosen coupling, as an
axial force on the pump shaft must be avoided.
3.3 Orientation
The pump can be mounted/orientated in any
direction.
3.2 Direction of rotation
Is indicated by means of an arrow at the label of
the pump.
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180R9277 | AN103586502885en-000501
© Danfoss | DHS (im) | 2020.08
Instruction Pump instruction PAH / PAHT 2-12.5
3.4 Protection from too high pressures
The pump should be protected against too high
pressure by means of a pressure relief valve or a
bypass/unloading valve placed on the pressure
side.
The valve should be placed as close to the pump
as possible.
3.5 Connections
The opening characteristics of the valve must not
result in peak pressures higher than 200 bar
(2900 psi).
The valve outlet must not be connected directly
to the pump suction line. It shall be connected
directly to the tank.
Thread size
Max tighten
torque
P: Pressure
T: Tank
C: Bleeding
D: Parallel key
5 x 5 x 20,
DIN 6885
PAH / PAHT 2-6.3 PAH / PAHT 10-12.5
P T C P T C
G 1⁄4 x 11 G 1⁄ 2 x 15
25 Nm 25 Nm 5 Nm 25 Nm 25 Nm 15 Nm
M6; Allen key
4 mm
G 3⁄8 x 15 G 3⁄4 X 17
G 1⁄4, NV6
14 deep
© Danfoss | DHS (im) | 2020.08
Recommended torque values refer to steel washers containing a rubber sealing element.
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Instruction Pump instruction PAH / PAHT 2-12.5
4. Initial start-up Before start-up, loosen the top bleeding plug “C”.
5. Operation
When water appears from the bleeding plug,
retighten the plug. With its inlet line connected
to the water supply or the tank, the pump is now
started with open outlet port.
At the initial start of the system, the pump
should be run without pressure for about 5
minutes, thus removing possible impurities from
pipes, hoses, etc. However, the system should be
ushed before start-up.
Warning:
Make sure that the direction of rotation of the
electric motor corresponds to the direction of
rotation of the pump. Otherwise the pump will
be damaged if a check valve is placed between
pump and tank.
5.1 Water quality
Water of drinking water quality, conrming to
the EEC directive 98/83/EC and without abrasive
sediments. Please contact Danfoss sales
organization in case of doubt.
5.2 Temperature
5.5 Disconnection
If the inlet line is disconnected from the water
supply, the pump will be emptied of water
through the disconnected inlet line.
When starting up again, follow the bleeding
procedure described under section 4: Initial start
up.
Fluid
temperature
Ambient
temperature
Storage
temperature
In case of lower operating tempera tures, please
contact the Danfoss Sales Organization.
5.3 Pressure
The inlet pressure must be between min. 0 barg/
0 psig and max. 4 barg/60 psig. The use of pump
outside this range damage the pump.
Max. pressure on the pump’s outlet line should
be limited at 140 barg (2030 psig) continuously.
NB: The pump unit should include a pressure
gauge on the high pressure side.
5.4 Dry running
When running, the pump must always be
connected to the water supply in order to avoid
damage if it should run dry.
In systems with water tank it is recommended to
build in a level gauge in the tank to avoid the risk
of running dry.
Min. +2° C to
max. +50° C
Min. 0° C to
max. 50° C
Min. -40° C to
max. +70° C
5.6 Storage
When preparing the pump for long-term storage
or for temperatures below the freezing point,
ush the pump with an anti-freeze medium type
monopropylene glycol to prevent internal
corrosion or frost in the pump. For further
information on anti-freeze media, please contact
the Danfoss Sales Organization.
Recommended procedure
5.6.1 Water hydraulic systems, water recircu-
lated
1. Disconnect the power pack from the
system.
2. Empty the tank of water. Fill up the tank
with anti-freeze medium to a level well
above the suction line.
3. Start up the power pack and, for a couple
of minutes, in a closed loop system let the
anti-freeze medium run back to tank
through the pressure relief valve or the
bypass valve.
4. Empty the tank of the anti-freeze medium.
Empty the pump through the lower
bleeding plug.
The pump is now protected against internal
corrosion and frost.
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180R9277 | AN103586502885en-000501
© Danfoss | DHS (im) | 2020.08
Instruction Pump instruction PAH / PAHT 2-12.5
5.6.2 Open-ended systems with water supply
from tank.
1. Empty the tank of water and empty the
pump housing through the lower bleeding
plug. When the pump is empty, retighten
the plug.
2. Through the upper bleeding plug, ll the
pump housing with anti-freeze medium.
Pour anti-freeze medium into the tank.
Connect a hose to the outlet of the pump
and lead the other end of the hose back to
tank.
3. Quickly start and stop the pump. Make sure
that the pump does not run dry.
The pump is now protected against internal
corrosion and frost.
6. Service The Danfoss PAHT pumps are designed for long
periods of service-free operation to provide
customers with low maintenance and life cycle
costs. Provided that the pumps are installed and
operated according to Danfoss specications, the
Danfoss PAHT pumps typically run 8,000 hours
between service routines. However, the service
schedule for your PAHT pump may vary according to the application and other factors.
The life of a pump may be greatly shortened if
Danfoss recommendations concerning system
design and operation are not followed.
5.6.3 Open-ended systems with direct water
supply.
1. Disconnect the water supply to the pump.
2. Through the lower bleeding plug, empty
the pump housing of water and close it
again.
3. Connect the pump to a tank of e.g. 25 litre/
6 gal. of anti-freeze additive. Connect a
hose to the inlet port of the pump and via
another hose return the ow from the
outlet port port to the tank with anti-freeze
additives.
4. Quickly start and stop the pump. Make sure
that the pump does not run dry.
The pump is now protected against internal
corrosion and frost.
Other factors that aect pump performance and
lifetime include:
• running the pump at speeds outside
specications
• supplying the pump with water at temperatures higher than recommended
• running the pump at inlet pressures
outside specications
• running the pump at outlet pressures
outside the specications.
7. Recommended service
intervals
In our experience, poor ltration is the number
one cause of pump damage.
7.1 General information
This guideline provides information on the
recommended service intervals for the PAHT
pumps. The recommendation is based upon
good engineering practice and on experience
gained from operation even under extreme
conditions.
The recommendation is for guidance only.
7.2 Inspection of pump parts
Danfoss recommends to inspect the pumps after
8,000 hours. Typical signs of wear are seen on the
contact/sliding surfaces in the pumps. If the
pumps must run for additional 8,000 hours, the
following parts will have to be inspected:
• Pistons
• Retainer plate, ball and bearing
• Valve plate
• Port plate
• Sealings
If service inspection due to the application is
complicated, the plant operator can decide to
extend the service interval by evaluating the
following deviations:
• Sound - does the pump have any unusual
sounds?
• Electric motor power consumption and
speed compared with measurement made
in the past.
• Pressure/ow according to measurements
made in the past?
We advise that the above mentioned parameter
during the extended service interval is inspected
for every 500-2,000 hours beyond the 8,000
hours. The pump must in any case be inspected
after maximum 16,000 hours or 2 years.
7.3 How to inspect the pump
Service manuals are available on the internet
www.danfoss.high-pressurepumps.com
© Danfoss | DHS (im) | 2020.08
If there are any wear marks on the parts they
need to be replaced.
180R9277 | AN103586502885en-000501
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Danfoss A/S
High Pressure Pumps
Nordborgvej 81
DK-6430 Nordborg
Denmark
© Danfoss | DHS (im) | 2020.08
180R9277 | AN103586502885en-000501 | 10
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