180R9289 | AQ109686503106en-001102 | 49
© Danfoss | 2023.01
Operation guide
Installation, Operation and Maintenance Manual for PAHT 256-308 pumps
Recommended procedure:
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 containing
anti-freeze additive. Connect a hose to the
inlet port of the pump and via another
hose return the flow 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.
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 there are any wear marks on the parts they
need to be replaced.
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/flow 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
hpp.danfoss.com
7.
Recommended service
intervals
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 specifications,
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.
In our experience, poor filtration is the number
one cause of pump damage.
Other factors that affect pump performance and
lifetime include:
•
running the pump at speeds outside
specifications
•
supplying the pump with water at temper-
atures higher than recommended
•
running the pump at inlet pressures
outside specifications
•
running the pump at outlet pressures
outside the specifications.
Instruction