York YCSA 120 T Technical Information page 45

Antifreeze protection
If temperature sensor B6 (leaving water) detects a tempera-
ture below the antifreeze set point, the unit will be blocked
and in alarm status (manual reset).
Simultaneously, the protection heaters of the plate exchanger
(output N11) are turned on. If the unit includes a hydro kit, the
protection heaters of the accumulator tank will also turn on.
These heaters will be turned off when sensor B6 detects a
temperature equal to the antifreeze set point plus a prees-
tablished differential.
The antifreeze system will operate regardless of the status
or mode of the unit.
The start-up of the pump and the unit can also be included
as antifreeze protection (please see parameters in the An-
tifreeze menu).
Backup heater
Once the preestablished period of time is over, after unit start-
up in heat mode, and the leaving water temperature detected
by B6 has not reached a minimum value, backup heater
output N12 will be activated. Once the water temperature has
reached said minimum value, plus a preestablished differen-
tial, this output will be deactivated (please see parameters in
the Antifreeze menu).
Remote ON/OFF
A remote digital ON/OFF input can be installed between
terminals ID3-G0, enabling it by means of the corresponding
parameter on the H - unit config. menu.
If the contact is open, the unit will remain OFF. If this contact
is closed, the unit will be ON.
If the unit is OFF during this digital input, a message will ap-
pear on the user display indicating this situation.
The unit will remain OFF as long as any of its inputs (user
keyboard, digital or monitoring input) is OFF.
Remote COOL/HEAT
A remote digital COOL/HEAT input can be installed between
terminals ID15-G0, enabling it by means of the corresponding
parameter on the H menu.
If the contact is open, the unit is in HEAT cycle. If this contact
is closed, the unit will be in COOL cycle.
If the digital COOL/HEAT input is enabled, this selection
cannot be made from the user or monitoring keyboard. To
change the cycle, whether from the digital input or the user
or monitoring keyboard, the unit must be turned OFF first.
If the digital COOL/HEAT input is not enabled, this selec-
tion can be made from either the user or the monitoring
keyboard.
Second pump
A second pump can be enabled within the system by means
of the H-unit config. menu. To do this, install its contactor (coil
230-1-50) between terminals N8-N, and the corresponding
protector (NC contact) between terminals DI18-G0.
This second pump will operate alternatively with the first
pump, depending upon the number of run hours or start
cycles. In the case of a failure of one of the two pumps, the
available pump will star immediately.
Upload key
The µC3 central module is equipped with a connector (J11)
for connecting an upload key (PSOPZKEYAO) to the unit
operating program.
Monitoring serial connection
The µC3 controller allows connection to a monitoring system
having an RS485 serial board. By using menu H-unit config.,
this function can be configured and enabled. This system has
two monitoring protocols: Carel and Modbus.
AUTO-RESTART
After the unit has been turned off due to a power failure, it
will retain the same operating mode and status it was in prior
to said power failure.
Alarm system
When an alarm is generated, the upper left key of the user
keyboard-display turns red.
Pressing this key displays the cause of said alarm. Then the
Up or Down keys must be pressed to check for any further
causes, which will appear on the display successively.
When the alarms are of the automatic reset type, unit opera-
tion will be reestablished once the causes have disappeared.
If the failure is of the manual reset type, once the cause has
disappeared, the Alarm key must be pressed to reestablish
unit operation. Then press the Esc key to go back to the
start screen.
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