34 DKDHR
VI.GP.V2.02
Danfoss District Energy
Instructions
Akva Lux II VX
15.0 Maintenance
Maintenance work
Is only to be carried out by qualified and authorised personnel.
Inspection
The water heater should be checked regularly by authorised personnel. Any neces-
sary maintenance must be performed in accordance
with the instructions in this manual and other sets of instructions.
During service the dirt strainers are to be cleaned – including the filter on the
controller, all pipe connections must be tightened and the safety valve must be
function tested by turning the lever.
Rinsing/cleaning of plate heat exchanger
To clean the plate heat exchanger, rinse it by running clean water through the
exchanger at high speed and in the opposite direction to the normal flow. This
will remove any dirt deposits that may have built up in the exchanger. If rinsing
with clean water is not sufficient, the exchanger can also be cleaned by circulating
a cleaning agent approved by Danfoss (e.g. Radiner Fl cleaning fluid) through the
exchanger. Both these cleaning fluids are environmentally friendly and can be
disposed off through the standard sewer system. After use of a cleaning fluid, the
plate heat exchanger must be rinsed thoroughly with clean water.
Acid cleaning of plate heat exchanger
Deposits of limescale may build up in plate heat exchangers for domestic hot water
on account of the large temperature fluctuations, and because aerated water is
used on the secondary side. If it becomes necessary to clean the exchanger with
acid, this can be done as shown on the drawing to the right. Brazed plate heat
exchangers can withstand rinsing with a dilute acid sulution - e.g. 5% formic, acetic
or phosphoric acid).
Measures after maintenance work
After maintenance work and before commissioning:
– 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.
– Clear all tools, materials and other equipment from the working area.
– Connect to energy supply and check for leaks.
– Vent the system.
– Carry out any necessary adjustment again.
– Make sure that all safety features on the device and the system work properly.
Meter reading
The caretaker/owner must perform visual checking and reading of the district
heating meter at short, regular intervals. (The meter is not a part of the delivery
from Danfoss). Service procedures must only be performed by trained, authorised
personnel.
NB! Excessive consumption for whatever reason is not covered by the Danfoss
warranty.
Cooling / Return temperature reading
Cooling – i.e. the difference between the supply and return temperature
of the district heating water – has a significant effect on overall energy economy.
Therefore, it is important to focus on the supply and return temperature in the
heating system. The difference should typically be 30–35°C. Please note that a low
district heating return temperature is directly related to the return temperature from
the heating circuit and the return temperature of the circulation water.
It is therefore important to focus on 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 authorized personnel immediately.
Please note that the connections may be supplied with EPDM rubber gaskets.
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.
