Danfoss District Energy
DSA 1 MINI -
13
13
Danfoss District Energy
VM.HE.B2.02
DEN-SMT/PL
Maintenance plan
10.0 Maintenance
Maintenance work
Is only to be carried out by qualified and authorised
personnel.
Inspection
The operator or other authorised personnel is obliged to
perform inspections at regular intervals and if necessary
carry out maintenance work according to these and other
instructions. Within the scope of the above maintenance
work all strainers should be cleaned, all connections should
be tightened and the operation of the safety valves should be
checked by turning the valve head in the indicated direction.
Rinsing/cleaning of plate heat exchanger
Brazed heat exchangers can be rinsed. For optimum cleaning
the flow rate should be a min. of 1.5 times normal flow rate,
preferably in back-flush mode. This will remove any deposits
formed on the inside of the plate heat exchanger. In case of
more serious deposits, a cleaning liquid, approved by
Danfoss (f.ex. Kaloxi or Radiner FI) can be pumped through
the heat exchanger. Both are environmentally friendly
cleaning fluids and can be disposed of through the usual
domestic sewerage system. Afterwards rinse thoroughly
with large amounts of water.
Deacidification of plate heat exchanger
After long operation, because of the relatively high
temperatures in the plates or tubes, the heat exchangers are
expecially subject to calification. Any deacidification of the
plate heat exchanger is done as shown on the drawing to the
right. For brazed plate heat exchangers weak inhibited acid
solutions (e.g. 5% formic, acetic or phosphoric acid) may
be used.
Measures after maintenance work
After maintenance work and before switching the system
on again:
– Check that all screwed connections are tight.
– Check that all safety features, covers, that were removed,
have been replaced properly.
– Clean the working area and remove any spilled materials.
– Make sure that all tools, materials and other quipment that
were used, have been removed from the working area.
– Connect to energy supply and check for leaks.
– Vent the system.
– If necessary adjust the system again.
– Make sure that all safety features on the device and the
system work properly.
For the janitor or other supervisors
Meter reading
It is recommended to read the heat meter at regular
intervals, and to write down the meter readings.
Cooling / Return temperature reading
The cooling, i.e. the temperature difference between district
heating supply and district heating return is of great impor-
tance for the total heat economy. It is therefore very impor-
tant to observe the supply and return temperatures. Normal
temperature difference is 30-35 °C.
Please note,
that the lowest district heating return tempera-
ture is directly dependent on the return temperature from
the heating circuit and the cylinder circuit. Therefore, please
observe these return temperatures.
Tightening of connections
When reading the heat meter, all fittings and connections
should be checked for leaks. If leaks are detected, contact
qualified and authori-zed personnel immediately.
Please note that the connections may be supplied with
EPDM rubber gaskets - in general connection sizes
from ¾” to and incl. 1½” for Kompakt H stations.
Therefore take care not to overstrain the union nuts,
as this may result in leaks.
The manufacturer accepts no
liability for leaks that result from overstrain of union nuts.
