Operation Of Motor Pump Unit; General Safety Information; What To Listen And Look For; Maintenance And Service Of The Pump Unit - Danfoss PAHT Operation, Installation, And Maintenance Manual

Operation guide
6. Operation of motor
pump unit
7. Maintenance and
service of the pump
unit
© Danfoss | 2023.12
Installation, Operation and Maintenance Manual for PAHT 20-90 pumps

6.1 General safety information

Before inspecting the pump unit, read the Safety
chapter 2 in this user manual.

6.2 What to listen and look for

If one or more of the following examples are
observed, please act as indicated:
A) Loose bolts – check all bolts and, if
necessary, contact the maintenance depart-
ment in order to have all bolts tightened to
the speci ed torque(s).
B) Leakage – if a small leakage from the bell
housing is observed. Contact the mainte-
nance department.
C) Leakage – if there is a large leak, the unit
should be stopped immediately. Contact
the maintenance department.
D) High frequency tones – safety/relief valves
are either damaged or running very close
to their design pressure, stop the unit
immediately. Contact the maintenance
department.
E) Increased noise or vibration – requires the
unit to be stopped immediately. Contact
the maintenance department.
7.1

General safety information

Before servicing the pump unit, it is necessary to
read and understand this user manual, especially
the Safety, chapter 2. Remember to wear suitable
safety equipment according to Safety, chapter 2.
7.2 Service and inspection interval for the
pump
Maintenance and service intervals are depending
on the cleanliness level of the water, hydraulic
load and temperature of the pump unit. The
most important parameter is the ltration of the
water.
See the section Service and warranty in the
appendix 1, Data sheet and appendix 2, Instruc-
tion.
For spare parts and service tools, please see
appendix 4, Parts list.
F) Very high temperatures – may indicate that
one or more parts are damaged inside the
pump. The pump must be stopped
immediately and inspected before it is
restarted. Contact the maintenance
department.
G) Drop in ow and/or pressure – may indicate
wear on one or more parts inside the pump.
The pump must be stopped immediately
and inspected before it is restarted.
Contact the maintenance department.
H) Other observations or troubles, please see
appendix 7, Right and Wrong or appendix
6, Trouble shooting guide. Both appendices
give good advises on design, installation,
wiring and troubleshooting.
If the pump is not stopped for inspection as
recommended, it can lead to damage of the
pump or break-down. See also service and
warranty section in appendix 1, Data sheet and
appendix 2, Instruction.
Danfoss o ers service of the pump at the system
manufacturer's location as well as we o er
training in how to service the pump. Quotes are
o ered upon request.
Danfoss recommends simultaneously to check
the lter and membrane condition and to
evaluate contamination; lter and membrane
elements must be replaced if necessary.
Danfoss o ers service of the pump at the system
manufacturer's location and training in how to
service the pump. Quotes are o ered upon
request.

7.3 Shut down of the system

A) Stop the high-pressure pump.
B) Release the pressure.
C) Stop the feed pump if used.
D) Switch o the safety circuit breaker for both
the high-pressure pump, feed pump and
VFD and lock them. Only personnel
servicing the pump unit should be able to
unlock/activate the switch again.
E) Open bleeding and drain plugs. Wait until
the pump and system are emptied for
water.
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