Automatic Cancellation Of Failure Warnings; Supply Air Temperature Control And Compensation; Supply Air Temperature Limits; Changing Of Temperature Settings According To Heating Season - Salda MCB Technical Manual

5.22. AUTOMATIC CANCELLATION OF FAILURE WARNINGS

This function is intended for the automatic elimination of freezing-related breakdowns after a certain period of time. E.g., if the unit was shut down
due to critical frost protection conditions, then after some time the system can try operation again. The period is indicated in hours. If 0 is set, the
system waits until the user cancels the failures manually.

5.23. SUPPLY AIR TEMPERATURE CONTROL AND COMPENSATION

Temperature for supply air or premises temperature may be indicated. In the service environment section SERVICE › MAIN › SUPPLY AIR TEMPERA-
TURE CONTROL you can control it based on supply or exhaust air temperature. If control by premises temperature is selected, then it is calculated
what kind of air is to be supplied so that the proper room temperature is maintained. It is limited by allowable limits of supply air temperature.
The air handling unit is not designed to heat premises, therefore it is not necessary to use full capacity for low temperature differences – the
compensation in percentage is provided for this purpose. This parameter indicates a percentage of the temperature difference (between the set
temperature and premises temperature) to be compensated by this function. E.g. set point is 20 °C, temperature in the premises is 16 °C, compen-
sation is 50 %, difference between the indicated and existing temperatures is 20-16=4 °C. Since 50 % is compensated, then 4*50 %=2 °C. When
the received value is added to the set temperature we get the required supply air temperature – 2+20=22 °C. This temperature is not limited as it is
within the supply air temperature protection limits. In this case the system maintains the supply air temperature at 22 °C. The closer the premises
temperature is to the set temperature (20 °C), the faster the supply air temperature reaches 20 °C.
It may be too hot in the premises, therefore this function both heats and cools. Preferred (compensated) temperature is displayed in the window
MONITORING (REQUIRED SUPPLY). If the displayed temperature is 0 °C, it means that temperature maintaining of supply air is switched off.
It is also possible to specify an integration factor that will gradually change the required supply air temperature without reaching the required ex-
tract air temperature. The higher the factor, the faster the required supply air temperature changes.
The temperature of supply air is maintained by the following components (indicated in a sequential order):
› Fans (operate slower, if it is too hot);
› Recirculation valve (if the ambient air temperature is favourable);
› Water cooler;
› DX cooler;
› Recirculation damper and CO
perature);
› Bypass damper or rotor (in case of favorable outdoor temperature);
First of all the system tries to maintain the supply air temperature by means of a heat exchanger. In case of a plate heat exchanger, the bypass
damper is controlled, and in case of a rotary heat exchanger, the rotor rotating speed or interval is changed. The heat exchanger can both heat
and cool – it depends on outdoor and room air temperatures. It is controlled by a PID controller whose coefficients are indicated in the adjuster
environment section ADJUSTER › PID CONTROLLERS ADJUSTING › HEAT EXCHANGER CONTROL BY SUPPLY AIR TEMPERATURE.
When the heat exchanger operates at full capacity and preferred temperature is not reached, the recirculation damper, then the heater or cooler
etc. is activated (if necessary). Only the components configured for temperature maintaining are activated. It takes 10 s for the system to switch
between the elements.

5.24. SUPPLY AIR TEMPERATURE LIMITS

In the service environment section SERVICE › MAIN › SUPPLY AIR TEMPERATURE LIMITS the minimum and maximum supply air temperatures are indi-
cated as well as permissible time and protection actions (no indication, indication of warning only, or unit shut-down). This function limits the supply
air temperature set by the user and other functions. If it is controlled by premises temperature, this function does not allow supplying warmer or
cooler air than that indicated in the protection.
If the system fails to maintain the right temperature, i.e. the supply air temperature is outside the protection limits for an indicated time period, the
unit is shut down (if indicated) and alarm is displayed. Based on manufacturer set parameters (by default), the minimum permissible supply air
temperature is 16,5 °C, and maximum – 40,0 °C.

5.25. CHANGING OF TEMPERATURE SETTINGS ACCORDING TO HEATING SEASON

This function is used to automatically change the temperature settings according to the season. As the heating season changes, the change from
heating to cooling is added to the temperature settings for all modes (building protection, economy, comfort) and subtracted when changing from
cooling to heating season.
The change can range from -15
The default is 0C, so the temperature settings do not change with the heating season. Function settings in debugger environment in ADJUSTER ›
USER SETTINGS › WINTER/SUMMER › TEMPERATURE SETPOINT CORRECTION ON SEASON CHANGE.

5.26. THE SYSTEM MODE COMMUNICATION WITH EXTERNAL CONTACTOR

This function activates the preferred system switching on by means of external contactor; it indicates what signal will be sent to input. Possible
types of signals:
› Not used;
› Upon pressing a button the selected system mode is activated. After receipt of the first impulse the function is activated, and after second
impulse – deactivated;
› ON/OFF; selected system mode is activated. The mode is active until the contactor is on;
› PIR sensor. When the sensor is activated, the selected system mode is activated. If the signal is not received for 30 minutes, the mode is
activated.
Function is set in the service environment section SERVICE › MAIN › SYSTEM MODE SWITCH.
10 | EN
(in case of favorable outdoor tem-
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C to +15 C. Addition or subtraction is limited by the permissible minimum and maximum supply air temperatures.
o o
› Recirculation damper and CO
perature);
› DX heater;
› Water heater;
› Water cooler/heater;
› Electrical heater;
› Fans (operate slower, if it is too cold).
(in case of favorable outdoor tem-
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MCB_miniMCB v2019.1