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Heat recovery unit KWLC 350
very likely that condensation will occur. Thus the temperature in the heat exchan-
ger must not drop so low that the water in it freezes. With the drop of the outside
temperature the heat exchanger temperature drops as well. When the heat exchan-
ger temperature drops to +2°C the intake air fan switches off until the heat exchan-
ger has warmed up sufficienty. The frost protection thermostat (3) is factory set and
normally needs no adjustment. Note: the use of the pre heating element will avoid
ice build up to much lower outside temperatures.
– Summer Service
During the warmer summer months when it is not necessary to recover heat, the heat
exchanger can be replaced with a summer insert. Then outside air comes directly into
the house without being warmed up. Make sure that the temperature sensor is set to
a low temperature (e.g. +18°C) in order to avoid unwanted heating up inside the buil-
ding. In the autumn, the summer kit must be replaced with the heat exchanger and
the temperature sensor should be adjusted accordingly.
Note:
Before first use, the summer insert has to be assembled as shown in picture 2.
Remember to reset the thermostat the following autumn and to mount the heat
exchanger unit again.
Pict. 2
MAINTENANCE:
The unit should be isolated from the mains before any servicing starts.
Opening of access doors
Open the clamps (14). Then remove the access door completely (12/13). To repla-
ce the door - fit back into the frame and clamp in place.
Attention: The unit has an access door on both sides so that entry can be made
through the side required.
Filter
The unit comes complete with filters (DIN EN 1946, T.2):
• Outside air: pre filter G3 and fine filter F5
(also available: optional pollen filter F7)
• Extract air: pre filter G3
Spare filter set 2x G3 + 1x F5
Spare filter set 2x G3 + 1x F7
The outside and the extract prefilter are to be changed or cleaned at least every
three months. The fine filter should be replaced at least once a year of use for hy-
gienic reasons. When replacing the filter the correct air flow direction through the
filter has to be observed. When the outside air is very dirty an air filter box (LFBR
250, ref.-no. 8580) should be fitted in the ductwork and the filter should be clea-
ned or replaced frequently.
Filter control
To monitor the filter, a differential pressure switch (accessory DDS switch, Ref.-no.
0445) can be connected to the KWLC. The knock outs for the pressure hoses (18)
are already drilled and connected with duct adapters. Remove link "FI" on the el-
ectrical terminal board. Then if the fiIter is dirty, the lamp on the control panel will
light up.
– Fans
The fans are to be maintained and cleaned once a year at least. For cleaning use
a small brush and an oil free cleaning fluid. Make sure that no water gets into the
motor. Fan must be completely dry before re-using. To remove the fan,
ELF-KWL 350/3/3/5
ELF-KWL 350/3/3/7*
unplug the electrical plug-socket facility. Loosen the four screws (16) and re-
move it carefully by pulling. To remove the right fan loosen the two side screws
(15) and pull the fan towards you. Then the fan can be removed like the other one.
Ensure that the balancing clips are not removed from the impeller.
Heat exchanger battery
Must be cleaned at least twice a year. Pull out the unit carefully. For cleaning put in
warm soapy water (do not use cleaning fluid containing Natriumcarbonate) and fi-
nally clean with warm water. When re-assembling ensure correct installation and
take care not to damage the seals.
Room grilles: To be cleaned at least annually.
Outside grilles: Check yearly that grilles are free from leaves etc.
SOURCES OF MALFUNCTIONING
Before working on the unit make sure that it is fully isolated from the supply.
– No air flow
• Check electrical connection / fuses
– Inlet air is cold
• Set heater thermostat (1) to a higher temperature
• Ductwork in cold areas need extra insulation.
• Make sure that summer-insert was changed for the heater exchanger.
• The overheating thermostat (2) may have tripped. Remove white plastic cap
and press red button.
– Substantially reduced air flow
• Filters (5 and 6) could be dirty. Change or clean them (see maintenance)
If any of the above points do not help please contact HELIOS.
Please state serial number given on the rating plate which is near the thermostat
of the heating coil.
Do not try to repair the unit yourself.
(pic. 5)
Ref.-No. 0024
Ref.-No. 0025
(pict. 5)
3
(picture 5)
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