Controlled Devices; Post Heating - Daikin UATYA-BBAY1 Manual De Operación

5.9.1

Controlled devices

The controller controls the devices installed in the unit, which may include:
- electrical heaters, divided by either one or two power steps;
- a hot water coil, with an analogue signal to control opening of a valve and a digital OK signal to control a pump
that gets started as soon as the valve opens. This management logic includes the anti-freeze function;
- a boiler that is controlled by an analogue signal and a digital OK signal which gets enabled as soon as an analogue
demand is received. This management logic includes a digital input through which the controller receives alarms
from the boiler, if any, as well as an anti-freeze function;
- a burner that is controlled by an analogue signal and a digital OK signal which gets enabled as soon as an
analogue demand is received. This management logic includes a digital input through which the controller
receives alarms from the burner, if any.
Parameter "STH55" is used to enable auxiliary heating for:
- summer operation only, in which case it serves as post heating during the dehumidification cycle;
- winter operation only, in which case it serves either as single source, if the refrigerant circuit does not feature
cycle reversal, or as an integration to heating where the latter is implemented by the refrigerant circuit;
- both summer and winter operation.
Anti-freeze function
The anti-freeze function, which is included in versions featuring a hot water coil and a boiler, is enabled when the unit
is in operation, no heating demand is present and the external air temperature is lower than the setpoint in parameter
"STH136".
In versions with a hot water coil, when the anti-freeze function gets enabled, the controller opens the relevant control
valve at the value set in parameter "STH137" and it enables the circulation pump.
In versions with a boiler, when the anti-freeze function gets enabled, the controller outputs to the boiler the demand
signal as set in parameter "STH137" and an OK signal for activation.
5.9.2

Post heating

When the value in parameter "STH55" is "1", auxiliary heating is configured for summer operation only and serves
as post heating during dehumidification. The control can either be proportional or PID, depending on the value set in
parameter "STH57". The value in parameter "STH56" identifies the probe taken as reference for the control which is
performed according to parameter "STH58".
Translation from original instructions
Packaged Rooftop
34
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UATYA