Daikin UATYA160BFC3Y1 [29/356] Phase sequence

Translation from original instructions

Packaged Rooftop

We reserve the right to make changes without any prior notice.

UATYA

4P645203-1

5.7 Power supply control

Units may be supplied with devices for protection against incorrect connections of the phase sequence or voltage

variations outside the required limits during operation.

Protections consist in relays which output an alarm signal to one digital input in the controller through an electric

contact (the digital input concerned is shown in the wiring diagram).

The unit can be tted with one relay to monitor correct phase sequence or one relay to monitor the power voltage or

one relay to manage both these functions.

5.7.1 Phase sequence

A dedicated relay is tted to manage incorrect connection of the phase sequence to the unit. If the phase sequence

is connected incorrectly, the relay opens an electric contact that triggers alarm “AL55” on the controller display.

Incorrect connection of the phase sequence may be experienced upon unit installation or when work is performed

on the power supply line.

Power must be cut out to the unit to make the connection correctly. The alarm is cleared as soon as the unit is

switched on again.

5.7.2 Min./Max.voltage

The controller is designed to manage potential conditions where the variation of the power voltage to the unit

experiences a signicant deviation from the expected values.

5.7.3 Fast Restart

Activation of the “Fast Restart” function, provided that an “ultracap” is tted to keep the controller electrically powered,

is designed to minimise as much as possible the delay experienced in restarting the compressors tted in the unit.

This is possible because the controller starts counting the minimum time to OFF as soon as a switch-o󰀨 is started

due to a blackout.

The controller detects problems with the main power supply through a digital input and manages them as alarms.

To protect the integrity of the compressors, the controller manages the maximum number of starts per hour by means

of the delay between two consecutive starts.

Quick restart after a blackout depends on the thermoregulation demand. It requires a demand for cooling or

dehumidication and the o󰀨-set for the activation of at least one compressor.

The “Fast Restart” function does not jeopardise the conditions of the compressors as it limits the number of quick

starts over the space of an hour or a day.