Functions; Internal Pre-Heater; Heat Exchanger Frost-Protection; Hot Water Heater Battery - Helios KWL EC 800 S Pro Montage- Und Betriebsvorschrift

Installation and Operating Instructions
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IMPORTANT NOTE
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NOTE
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KWL EC .. Pro WW
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ATTENTION
Central Ventilation Units KWL EC.. S Pro/WW
3.2

Functions

3.2.1 Internal pre-heater

According to criteria for passive houses, a pre-heater is mandatory to prevent the cross-counter flow heat exchanger
from freezing! The pre-heater is located behind the outside air filter F7.
The pre-heater is active to prevent the unit from icing up.
Important note:
The pre-heater only activates if the supply air ventilator is extracting the minimum flow rate and there are no errors. If
the KWL unit is switched to standby mode, the supply air ventilator will run for 60 seconds in case the pre-heater was
activated before that. If the pre-heater is previously activated and e.g. the unit is switched to standby 20 sec. later, the
supply air ventilator will then only run for 40 sec.
General information on the pre-heater
The pre-heater is equipped with two safety temperature limiters, the STL (auto reset = trigger temperature +50 °C) and
(manual reset = trigger temperature +115 °C) are connected in series. Once a safety temperature limiter is triggered, the
preheater will be disconnected from the power supply and an error will be displayed on the controller.

3.2.2 Heat exchanger frost-protection

The heat exchanger frost-protection function is divided into 3 steps:
1st step Pre-heater control
As soon as the exhaust air temperature (INT-2) falls below 5 °C, the frost monitor will activate. Depending on the speed
at which the exhaust air temperature falls below 5 °C to 3 °C, the pre-heater will be controlled at temperatures below
3 °C accordingly.
2nd step Pre-heating and opening the bypass shutter
If the exhaust air temperature remains below 2 °C with 100% pre-heater control, the bypass control will also start in
order to reach a temperature increase of more than 1°C.
3rd step Pre-heating, opening the bypass shutter and fan reduction
If the exhaust air temperature increase remains below 1 °C with full pre-heater control and the complete opening of the
bypass shutter, the supply air and extract air fans will be reduced to the minimum value.
Stop conditions for the heat exchanger frost protection
If the exhaust air temperature is increased to more than 3 °C, the bypass shutter control will end and return to normal
control. The pre-heater is only used for the heat exchanger frost protection at over 3 °C.
If the exhaust air temperature reaches more than 5 °C, the pre-heater control and thus the heat exchanger frost protec-
tion will end.

3.2.3 Hot water heater battery

A hot water heater battery ensures the comfortable and energy-efficient auxiliary heating of supply air. This is particularly
useful if the supply air (heated outside air from the heat exchanger) is to be heated to a higher temperature level
(normally room temperature or higher).
– Connection and regulation of internal hot water auxiliary heater (only type KWL EC.. S Pro WW)
The outside air and supply air which has been pre-heated by the heat exchanger can be additionally heated with the
internal hot water heater battery. A WHSH HE 24 V (0-10 V) (Ref. no.: 8318) is required for this (WHSH HE.. not included
in scope of delivery), and the circulating pump integrated in the WHSH HE.. must be operated at medium capacity.
When using the hot water heater battery, it must be ensured that the hot water supply is guaranteed at all times, for
example, to prevent frost damage to the heater. The hydraulic unit must be connected to the ventilation unit by a spe-
cialist.
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A cover flap must be mounted in the outside air and in the exhaust air on KWL EC .. PRO WW units to pre-
vent damage to the hot water heater battery!
Fig.10
Heating water connection for internal warm
water aux. heater. Connection thread IG ½
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