USER MANUAL FOR MK3 PANEL - COMPACT & SPLIT UNITS
The intervention of the safety pressure switch is caused by an excessive rise of the refrigerant pressure inside the
system.
If the system is functioning in cool mode the problem is caused by the lack of sea water cooling. It is necessary to
check the correct functioning of the sea water pump before resetting the system.
If instead the system is working in heat mode the problem is normally caused by lack of air flow. In this case we
suggest to rise the fan speed in order to increase the air flow.
For the procedure of troubleshooting please refer to the air-conditioner user manual.
HP PRESSURE SWITCH CUT-OUT
The MK3 control has a specific behaviour in case of intervention of the safety pressure switch,
When running in summer cooling (Cool mode): it stops the compressor and the sea water pump while the fan
keeps running. As the safety intervention might be a temporary problem, for the first two interventions the
compressor and pump stop for a given time (between 1.5 up to 6 minutes) and then automatically restart. The
indicating dot on the display is blinking during the stop time.
If the safety cuts for the third time, the display shows HP (high pressure) and the system remains locked-out
(everything stops) and needs a manual reset. Manual reset means switching off and on again with the ON/OFF
button..
ALARM INDICATIONS
System locked by safety cut
out (HP)
pag.8/8
When running in winter heating (Heat mode): it stops the compressor and the sea water pump while the fan keeps
running. As the safety intervention might be a temporary problem, for the first two interventions the compressor and
pump stop for a given time ( 2 minutes) and then automatically restart. The indicating dot on the display is blinking
during the stop time.
If the safety cuts for the third time, the display shows HP (high pressure) and the system remains locked-out
(everything stops) and needs a manual reset. Manual reset means switching off and on again with the ON/OFF
button.
ANTIFREEZE FUNCTION WITH OPTIONAL SENSOR
The MK3 control is ready to be connected to an optional antifreeze sensor which permits the operation of the system
under special conditions preventing alarm stops.
Connecting the antifree optional sensor automatically activates a protective function. If the sensor detects a
condition of possible icing of the evaporator, it starts a heat mode run for 1 minute which guarantees the melting of
the ice. After the heating cycle the air-conditioner restarts its normal cooling mode.
The antifreeze monitoring is activated every 15 minutes. This optional feature is available only for the RC – reverse
cycle versions.
C861-01 – 02/2014
