21. 07. 20. Leaflet Number 671748
19
XBOXER XBC 10-65 Ecosmart Connect (CO) Control
8.9 Trickle Mode
8.10 Frost Protection
8.11 Night Cooling / Summer Free Cooling
8.12 Purge Mode
8.13 Hibernate
When trickle mode is active, the fans will run at their minimum speed even when
there is no enable signal. Heating and cooling will also function in this mode if
available. While in trickle mode, the unit will function in “Supply Temperature
Control Mode” but with a different, wider deadband, set by the network input
Trickle Deadband.
Should the internal temperature of the unit fall below a value defined in the
commissioning variables, the control will override all heating/cooling logic to
open the LPHW or CW control valves, if fitted. This is to allow any protective
flow through the heating/cooling coils. The supply fan will also stop and the
appropriate frost protection software module will enter an alarm state. This
period will last for a minimum of 5 minutes by default. The fault relay will also
open. Heat and cool demand relays will operate and the software frost alarm
will enter an alarm state.
Please note that frost protection will only function if the Heating Type or
CoolingType setpoints are set to LPHW or CW.
Once enabled in software, this routine uses an individual time schedule to cool
the fabric of the building at night using only the external air. This mode only
functions if the daytime temperature is above the setpoint, cooling is possible
and if the cooling air is not too cold.
Once enabled in software, this routine uses an individual time schedule to
provide a period of increased air change throughout a space. This mode only
functions if the inlet air is above a minimum temperature of 12°C. While purge
is in progress, the unit will function in “Supply Temperature Control Mode” but
with a different, wider deadband, set by the network input “Trickle Deadband”.
This mode is available for LPHW and CW units where the valves are required
to be driven open in anticipation of a period where the unit is electrically
isolated and inactive. When enabled via the network input “Hibernate Mode”
this will stop the fans and open all LPHW & CW valves fully. The unit can then
be powered down. This mode activation is reset upon power cycle so when
restarted the unit will function as normal.
This mode is for periods when to building is left dormant and will stop the coils
trapping water and causing a freeze risk. It will be the buildings responsibility to
provide freeze-preventative heating during this time. This can also be used for a
cleaning or flushing cycle.
8.13.1 Thermal Trip
8.13.2 Maintenance Alarms (Non-Latching)
In case of software failure, as a final resort, the electric heater is protected by
a fail-safe thermal overload switch. This switch disables the heater controller
via a contactor once the temperature reaches 80°C. When this occurs, the
critical alarm will latch in software and the supply contactor will latch in the off
position.
Once the unit cools, the contactor will remain latched off until power cycle.
Once in maintenance alarm state the only action taken is de-energising of the
fault relay. Once the trigger is removed, the alarm will reset automatically.
Causes of critical alarm:
•Fan fail via fault circuit 1.
•Heater overtemp via fault circuit 1.
Causes of maintenance alarm:
• Sensor Failure
• Low supply temperature, default 8°C. This can be set to stop fans if
required
• Frost protection routine active, default 4°C (This only runs if water valves
are selected as fitted
•Excessively high supply temperature reading (This will stop heating)
• Filter dP fault (if fitted)
All alarms have a hold off period set by the setpoint “Alarm Delay”.
8.14 Alarms
8.14.1 Critical Alarm Latching
Once in critical alarm state the unit will drive all heating and cooling outputs to
0V. In the event of fan fail other functions continue as normal. The critical alarm
is latched and requires power cycle or reset via the “Reset Alarms” variable.
Causes of critical alarm:
• Fan fail via fault circuit 1
• Heater overtemp via fault circuit 1
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