Open-Ended Systems With Water Supply From Tank; Open-Ended Systems With Direct Water Supply; Service; Recommended Service Intervals - Danfoss PAHT 2 Operation, Installation, And Maintenance Manual

Operating guide
6.

Service

7. Recommended service
intervals
© Danfoss | 2023.09
PAHT 2-12.5 pumps
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.
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 speci cations,
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.
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
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.
In our experience, poor ltration is the number
one cause of pump damage.
Other factors that a ect pump performance and
lifetime include:
• running the pump at speeds outside
speci cations
• supplying the pump with water at temper-
atures higher than recommended
• running the pump at inlet pressures
outside speci cations
• running the pump at outlet pressures
outside the speci cations.
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/ 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
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