17
Meter reading
The caretaker/owner must perform visual checking and reading of the
district heating meter at short, regular intervals in accordance with
the maintenance plan, page 13. (Please notat that 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.
Inspection
The unit should be checked regularly by authorised personnel. Any
necessary 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 (
pos. 16
) must be function tested by turning the lever.
Always lead the blow-off pipes from the safety valves to a drain in
accordance with applicable legislation.
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 ex-
changer can also be cleaned by circulating a cleaning agent approved
by Danfoss (e.g. Radiner Fl cleaning fluid) through the exchanger. Use
an environmentally friendly cleaning fluid, which 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.
Venting
During start-up (of the heating season) always vent the radiator cir-
cuit/heating side, the pump and the unit. To vent the unit, use the
air valve
(pos. 17
) in the unit. Vent the radiator circuit/heating side
on the bleed screws of the radiators. Vent the pump according to
instructions in the pump manual.
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.
Cooling / Return temperature reading
Cooling – i.e. the difference between the supply and return tem-
perature of the district heating water – has a significant effect on
overall energy economy. Please note that the district heating return
temperature is directly related to the return temperature from the
heating circuit (and the return temperature from the DHW plate heat
exchanger). Therefore, it is important to focus on the supply and return
temperature in the heating system. The difference should typically be
30–35°C in systems that operate with radiators. In systems that feature
floor heating, the difference is typically 5–10°C. In these systems the
supply temperature should not exceed 35°C.
Tightening of connections
When reading the meter check that all connections are tight. If leaks
are found, contact authorized personnel immediately.
10. Operation and maintenance
Air valve
16
12
Instructions for installation and use
S 22
DKDHR
VI.IE.D1.02
Danfoss District Energy
