Bypass Function "Summer Operation; Frost Protection Cross Counter Flow Heat Exchanger - Helios KWL EC 220 D Eco R Montage- Und Betriebsvorschrift

Installation and Operating Instructions
Compact ceiling units KWL EC 220 D Eco

3 .1 .4 Bypass function "summer operation"

The automatic bypass function with exchanger cover (Fig.17) allows colder outside air directly into the room and ensu-
res a pleasant indoor climate by bypassing the heat exchanger by means of a servomotor-controlled bypass damper
(Fig.16).
Bypass closed: Outside air is led through a heat exchanger into the room (heat recovery active)
Bypass open: Outside air is led directly into the room (heat recovery inactive), indirect "cooling" of room air.
Potentiometer
with scale
– Functional description Bypass:
If the KWL is supplied with mains power, the bypass damper will close completely. The bypass temperature (extract air
temperature T3) is adjusted on the potentiometer (Fig.18/19). The bypass function can be deactivated via the potentio-
meter setting "OFF" (factory setting) (Fig.19).
The bypass is opened when all conditions are met:
Condition 1: The extracted air temperature (sensor T3) is higher than the bypass temperature.
Condition 2: The outside air temperature (sensor T1) is lower than the extracted air temp (sensor T3)
Condition 3: The outside air temperature (sensor T1) is higher than the outside air limit (factory setting +15 °C)
The bypass is closed if conditions 4 and 5 or 6 and 7 are met .
Condition 4: The extract air temperature (sensor T3) is lower than the bypass temperature which is reduced by -2 °C
(hysteresis).
Condition 5: The bypass is open
or
Condition 6: The outside air temperature (sensor T1) is lower than the outside air limit which is reduced by -2 °C.
Condition 7: The bypass is open

3 .1 .5 Frost protection Cross counter flow heat exchanger

The frost/freezing protection function prevents the freezing of the cross counter flow heat exchanger if the pre-heater is
not connected or the heating output is not sufficient.
– Functional description:
Frost-protection is active if the following conditions are met .
(This applies for units with and without pre-heater (accessories))!
The effects depend on the respective unit configuration (passive house or DIBt):
Condition I: The exhaust air temperature (sensor T4) is 2 °C lower than the frost protection setting (factory setting +3
°C) and is measured for longer than 2 min.
Configuration Passive house: Pre-heater is deactivated and the supply air fan is operated at the highest fan stage for 1
min. for safety reasons, the extract air mode is then active. If the exhaust air temperature exceeds the heat exchanger
frost protection temperature, the normal operating mode will be activated.
Fig .16
Bypass module with
damper for exchanger
Bypass damper
cover
(Fig. Cut through the
back of unit)
Fig .18
OFF
7
19°C
18°C 20°C
17°C 21°C
22°C
23°C
26°C 24°C
25°C
080-304
EN
Fig .17
Fig .19