Testing Of Fire Dampers; Heat Exchanger Control; Cold-Heat Recovery; Heat Exchanger Frost Protection - Salda MCB Technical Manual

The outdoor air recirculation dampers shall perform the following:
› Heat-exchanger deicing function;
› In stand-by mode full recirculation (blocking of outdoor air).
The supply and outdoor air recirculation dampers shall perform the CO
If the outdoor air recirculation damper is activated, then it is necessary to assign 0-10VDC output for its control.
outdoor air
outdoor air recirculation

5.34.4. TESTING OF FIRE DAMPERS

Fire dampers may be tested manually or automatically at indicated day intervals. Testing results are stored in event history. If testing fails, a warn-
ing is displayed. The user can indicate the damper testing hour (in user settings) as air-flow is then stopped. The necessary position in case of fire
is also indicated in the service environment.
The dampers are always monitored by the limit switches for the correct position. If not, the system is stopped and the damper fault is registered.
Response times are specified in the service environment as valves may sometimes be tested externally. Closing the dampers stops the flow of air.
Dampers are configured in the service environment window SERVICE › DAMPERS.

5.35. HEAT EXCHANGER CONTROL

5.35.1. COLD-HEAT RECOVERY

Cold-heat recovery function is designed to control a heat exchanger. Its power is controlled by:
› Using plate heat exchanger - bypass damper. When it is closed, the heat exchanger is operating at full capacity. Its power is reduced by
opening the damper.
› Rotary heat exchanger power is controlled by changing its rotating speed or interval. When the rotor rotates at full speed, the heat exchanger
is used at full capacity. The power is reduced by slowing down the rotating speed or increasing the interval. The heat exchanger can both heat
and cool – it depends on air temperature. If it is colder outside than in the premises, the heat exchanger pre-heats the outdoor air by using
the room heat. If it is colder in the premises than outside, the heat exchanger cools down the outdoor air temperature by room air. Its power is
reduced to the minimum when the target supply air temperature is the same as outdoor one. The higher the difference between the preferred
and supply air temperatures, the higher heat exchanger power is used. When it is operating at maximum capacity, it is allowed to activate
other heating/cooling components.
For this function suitable heat exchanger type is indicated in the window SERVICE › HEAT EXCHANGER and PID controller coefficients – in the window
ADJUSTER › PID CONTROLLERS ADJUSTING.
PID controller output limits are set for rotor or bypass damper, at which their operation starts.
› If rotor is controlled by 0..10 V signal, at low voltages it does not rotate, the motor heats up, thus the minimum control signal output is limited.
If On/Off rotary heat exchanger is used, PID percentage for activating the rotor is indicated in the window SERVICE › HEAT EXCHANGER.
› If the bypass damper opens only a few percent, noise can occur, thus the minimum its opening limit is limited, which also applies when com-
ing to the full opening. If the plate heat exchanger with a 3-way bypass damper is used, the opening time of the bypass damper is indicated
in the window SERVICE › HEAT EXCHANGER.
› If a plate heat exchanger with segment valves is controlled by an external controller is used, then the type of the bypass damper REMOTE
CONTROLLER is shown in the window SERVICE › HEAT EXCHANGER.
› If a plate heat exchanger with segment valves connected to a controller is used, then the type of the bypass damper is shown in the window
SERVICE › HEAT EXCHANGER as either 2 SEGMENTS or 3 SEGMENTS. In the case of heat recovery control, segments are closed in sequence, i.e.
if heat recovery is not required, then all the segments are closed and the bypass damper is opened.
When the fans are switched on during the heating season, the heat exchanger runs for 10 minutes at full power, until the system stabilizes.

5.35.2. HEAT EXCHANGER FROST PROTECTION

This protection is designed to protect the heat exchanger from the formation of ice inside because ice formations can damage the structure of the
heat exchanger. The protection is configured in the service environment, in the window SERVICE › HEAT EXCHANGER.
The protection can be activated/deactivated according to the following:
› Specified outdoor air temperature;
› Specified exhaust air temperature;
14 | EN
reduction function.
2
supply air extract air
supply air recirculation
MCB_miniMCB v2019.1
exhaust air