MSAT 102-122-142-162-182-202-242

HIGH PRESSURE SHUTDOWN
HIGH PRESSURE SHUT-DOWN
YES
Ventilation working
efficiently?
NO
Check the coil
( 1 )
Check the fan
( 2 )
Check the fan module
( 3 )
Check the probe
( 4 )
YES
Outside air temperature
lower than the operating
limits?
NO
Check the design data
( 5 )
YES
Refrigerant charge correct?
NO
Check liquid subcooling
( 6 )
YES
Absence of incondensables?
NO
Empty and recharge
( 7 )
YES
Intake temperature and/or
pressure correct?
NO
Check operation
of the indoor unit ( 8 )
Check operation of the
liquid line on-off valve
( 9 )
Unit working
Notes
The condenser must provide the maximum heat exchange, and as a consequence must be free of dirt, deposits or obstacles
to the flow of air.
2) Check the condition of the fan and replace it if damaged.
3) Check that the voltage output from the board proportionally modulates the fan speed. If not, replace the module.
4) Check the positioning: it must be in close contact with the shaped exchanger coil pipe. The resistance values must be
perfectly in line with the temperature; check the resistance values using a special ohmmeter.
5) Check:
- Operating limits. (see the general section)
- That the coil not is exposed to direct sunlight or placed near reflecting surfaces.
- That there are no hot air streams of any type in the immediate vicinity.
- That the same air is not recirculated.
6) For information on how to perform the checks, please refer to section on START-UP. NB the flooding of the exchanger coil
circuits to the point of the probe socket will cause the anomalous operation of the fan speed controller.
7) One condition that may arise is a very high condensing temperature (25/30 degrees above the air temperature) combined
with low refrigerant efficiency. This may cause the same symptoms as an excessive refrigerant charge. Check the charge
and, if correct, evaluate this possibility and perform all the emptying and charging operations again.
8) Check that the air flow-rate not is too high and that the ambient air temperature is not too high. These conditions may
increase the output of the machine and consequently the heat to be dispersed by the condenser.
9) Check that all the on-off devices on the liquid line are completely open.
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