Outdoor Air Water Pre-Heater Frost Protection; Coolers; Water Cooler; Freon Cooler - Salda MCB Technical Manual

5.36.7. OUTDOOR AIR WATER PRE-HEATER FROST PROTECTION

The minimum allowable return liquid temperature is indicated. If it drops below the indicated temperature, the unit is shut down and warning is
displayed. The most common liquid is glycol, therefore the protection must be set according to its parameters.
This protection also protects the pre-heater against cold air when starting up the system. If this unit is switched off in winter, it is automatically
pre-heated prior to starting up the fans, i.e. it is allowed to operate for the indicated time period at 100 %.
Protection is configured in the service environment window SERVICE › HEATERS.

5.37. COOLERS

In this system, when the heat exchanger cooling power is not sufficient, a water or freon cooler may be used. They help to reduce the supply air
temperature.
Indicates the water cooler water freezing point. Also freon cooler control type (ON/OFF or 0..10 V), the minimum time between ON/OFF, possibility
to switch to heating mode is set. In this case the deicing time is set.
Coolers are configured in the window SERVICE › COOLERS.

5.37.1. WATER COOLER

The water cooler can be used both as a cooler and a heater; therefore, it is necessary to specify whether the cooler is used only for cooling or for
cooling and heating.
The heating mode can be activated as follows:
› According to the heating season (according to the 3-day outdoor air temperature or the date)
› According to the return water temperature (limit: 20°C)
› According to the digital signal (external contact)
In the heating mode, the cooler operates according to the algorithms of the water heater.

5.37.2. FREON COOLER

For the freon cooler, the following is indicated: the control type (ON/OFF or 0..10 V), minimum interval between activation and deactivation, minimum
outdoor air temperature, and the possibility to switch into the heating mode. If the possibility to switch to the heating mode is activated, then the
deicing time is indicated.
If the freon cooling control is indicated as 0..10 V and the heating mode is active, then the automatics respond to the deicing status of the external
controller (transmitted through the Modbus communications line). If deicing is in progress, then the exhaust air fan is slowed down, the air heater
is activated at full capacity. After deicing, the exhaust air flow is increased and water drops are blown away.
The configuration of coolers in the window SERVICE › COOLERS.

5.37.3. THE MINIMAL OUTDOOR AIR TEMPERATURE OF THE FREON COOLER/HEATER

The minimal fresh air temperature, at which the DX cooler/heater can operate, is indicated. If the fresh air temperature drops below the specified
limit, then the DX cooler/heater is shut down.

5.37.4. THE FREON COOLER/HEATER AIR FLOW PROTECTION

The minimal supply air flow, at which the DX cooler/heater can operate, is indicated. If the supply air flow drops below the specified limit for more
than 60 s, then the DX cooler/heater is shut down and a warning message is shown.
Also, the maximal speed change of the supply air fan (in percentage points per second) is indicated when the DX cooler/heater operates. If the
DX cooler/heater operates, then the rapid switching of the supply air fan from one speed to another is restricted.

5.37.5. AUTOMATIC ADJUSTMENT OF DEFROST INTERVALS OF THE FREON COOLER/HEATER

This function is designed to automatically adjust the defrost intervals (using external controller) by monitoring the time of this process. Modbus
communicates the dynamic time interval settings from the MCB to the heat pump controller.
This function specifies the required initial interval between defrosting and the defrosting time (e.g. 3 min.). After defrosting, the automatics com-
pares how long this process lasted. If it lasts longer than specified, the time between defrosting is reduced by 5 minutes, and if shorter, then
extended by 5 minutes.
Maximum time between defrosting – 360 min.

5.38. DIGITAL INPUT CONFIGURATION

In this system you can set a normal state of every digital input, i.e. indicate whether the contactor is normally open or closed (NORMALLY OPEN (NO),
NORMALLY CLOSED (NC)). The fire protection contactor must be NC as in case of fire the contactor may break due to burnt cable.
Digital inputs are configured in the service environment window SERVICE › DIGITAL INPUTS.

5.39. SENSOR CONFIGURATION

In this system, three 0-10V DC sensors and eight temperature sensors can be used. The following can be connected to two 0-10 VDC inputs:
› supply air RH sensor;
› exhaust air CO sensor;
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MCB_miniMCB v2019.1 EN | 17