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The rooftop package units are factory pre-charged with suf
fi
cient refrigerant. However, there may be a need for charge recovery
during service and maintenance works. Therefore, some precautions must be taken to ensure optimum and trouble-free system
operation:
(i) The system should be throughly vacuumed to ensure no incompressible gas and moisture in the system.
(ii) Use a vacuum pump for R22 or R407C exclusively. Using the same vacuum pump for different refrigerants may damage
the vacuum pump or the unit.
(iii) The refrigerant should never be released directly into the environment.
(iv) When charging R407C, ensure that only liquid is being withdrawn from the cylinder or can.
Normally, the R407C cylinder or can is being equipped with a dip-pipe for liquid withdrawal. However, if the dip-pipe is
not available, invert the cylinder or can so as to withdraw liquid from the valve at the bottom.
TROUBLESHOOTING
If any malfunction of the air conditioner unit is noted for some simple trouble-shooting tips. Check the following
fault conditions and causes for some simple troubleshooting tips. For any enquiries on spare part, please contact you
authorized dealer.
Problem
Causes
Action
Unit does not run.
Power failure.
Press the [ON/OFF] after power restore.
Fuse blown or circuit breaker tripped.
Replace fuse or reset circuit breaker.
Power supply wiring phase incorrect.
Modify the wiring phase.
Compressor does not operate in 3 min
after unit has started.
Protection against frequent starting.
Wait for 3 min for the compressor to start.
Air
fl
ow is low.
Filter is
fi
lled with dust and dirt.
Clean the
fi
lter.
There are some obstacles at the air inlet or
outlet of the units.
Remove obstacles.
Compressor operate continuously.
Dirty air
fi
lter.
Clean the air
fi
lter.
Temperature setting is too low (for cooling).
Temperature setting is too high (for heating).
Reset the temperature.
No cool air delivered during cooling
cycle, or no hot air delivered during
heating cycle.
Temperature setting is too high (for cooling).
Temperature setting is too low (for heating).
Set the temperature lower.
Set the temperature higher.
On heating cycle, indoor fan stop
suddenly.
UAT(Y)(P)60, 80, 100, 120A
On heating cycle, delivered air does not
warm enough suddenly.
UAT(Y)(P)150, 200, 250, 300, 360, 420A
Unit is in defrosting cycle.
Wait for a while.
(It will be resumed after defrosting.)
If the fault persists, please call your authorized local dealer/serviceman.
VACUUMING AND CHARGING
Invert cylinder
without dip-pipe
Liquid
withdrawal
Dip-pipe
!
CAUTION
Do not top-up when servicing leak, as this will reduce the unit performance. Vacuum the unit thoroughly and then
charge the unit with fresh R22 & R407C according to the amount recommended in the speci
fi
cation.
•
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