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TM077: 325 & 410 Series II Heat Pump Service Instructions
Rev 00: Issued April 2014
Freeze Protection during Element Heating
– Fault
Whilst the Freeze Protection function is active, the main relay is energised meaning it is
possible for the compressor to receive power if a controller hardware failure exists.
Therefore if Freeze Protection is required during Element Heating
– Fault, it must still be
possible to monitor the condition of the compressor.
Therefore the Freeze Protection function is disabled under the following conditions:
If Fault 1 is current, as Fault 1 may indicate a compressor problem
If Fault 6 is current, as Fault 6 indicates the compressor temperature sensor has
failed and therefore the compressor condition can not be monitored
Whenever Fault 5 is current, the Freeze Protection function is also disabled as Fault 5
indicates the evaporator temperature sensor has failed and therefore it is not possible to
determine the need for Freeze Protection.
LED STATUS CODES
The 325 & 410 Series II Heat Pumps utilise a green and red LED to display information
about the operating status and/or fault conditions.
The green LED displays the operating mode; the red LED displays a fault condition. Refer
to the LED Status Code Tables on page 19 for the LED flash sequences and a description
of the condition.
In addition to displaying the current operating condition, the red LED is also able to display
the last fault condition that occurred, as this Fault Code is stored in the controller
‟s
memory. If a current fault is being displayed, this is the same Fault Code that is stored in
the controller
‟s memory.
To initiate the Last Fault Code function, turn the power off, wait 30 seconds then turn the
power back on again.
When power is restored to the system, the green LED will display a rapid flash during the 3
second System Start-Up process and the element operates.
If only the green LED illuminates after System Start-Up, a fault is not stored in the
memory.
If a fault has occurred in the past, the red LED will display the stored Fault Code for 27
seconds, then attempt normal operation. (For example, if the red LED displays 1 flash
–
Fault 1
– the compressor discharge temperature has exceeded 110°C during the last heat
pump operation).
NOTE:
Power must be available and the mechanical thermostat contacts must be closed
for this function to operate.
The element is energised whilst the red LED displays the stored Fault Code.
The stored Fault Code is automatically cleared from the controller memory each time the
heat pump completes a full cycle in Heat Pump Mode without detecting a fault, or when
the reset button is pressed.
