10
VUT 160/250/350 PB EC
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UNIT OPERATION MODES
Heat recovery mode:
warm stale extract air from the room flows into the unit, where it is filtered by the extract filter, then air flows
through the heat exchanger and is exhausted outside by the extract fan.
Cold fresh air from the outside flows into the unit, where it is cleaned by the supply filter.
Then the air flows through the heat exchanger and is directed to the room with the supply fan.
Supply air is heated in the heat exchanger by transferring the heat energy of warm and humid extract air to the cold fresh air. The air
flows are fully separated while flowing through the heat exchanger. Heat recovery minimizes heat losses, which reduces the cost of space
heating in the cold season.
EXTRACT AIR
SUPPLY AIR
INTAKE AIR
EXHAUST AIR
Freeze protection
(danger of freezing appears when the exhaust air temperature downstream of the heat exchanger is lower than
+5 °C and intake air temperature upstream of the heat exchanger is lower than -3 °C for the units with preheating, and when exhaust
temperature downstream of the heat exchanger is lower than +3 °C for the units without preheating). To protect the heat exchanger from
freezing in the cold season, the unit has a Frost Protection mode based on the temperature sensor readings.
The sensor is installed in the exhaust air duct downstream of the heat exchanger.
The Frost Protection mode is activated at an exhaust air temperature of +3 ˚С.
After temperature increase the unit returns to the previous operation mode.
In VUT 160/250/350 PB EC A11 units the frost protection mode must be activated, see the User’s manual of the control panel. In case of
freezing danger, the supply fan is turned off in VUT 160/250/350 PB EC A14 units. After temperature increase the unit returns to the previous
operation mode. The VUT 160/250/350 PB EC A21 units have three frost protection modes: - gradual reduction of the supply fan speed
- with the bypass - with the electric preheater (if the unit is equipped with a duct preheater). Mode selection and settings are described
in the User’s manual for the control system.
EXTRACT AIR
SUPPLY AIR
INTAKE AIR
EXHAUST AIR
