Instruction manual

OPERATION AND MAINTENANCE MANUAL
Wall Mounted 0121…0661
Monobloc Wall Mounted Unit - WMA/WMF 0121-0181-0251-0281-0331-0551-0661 - Rev. 2.0. - Date: 18-07-2000 EN
27 (32)
FANS
PROBLEM POSSIBLE CAUSE CHECK / REMEDY
LACK OF AIRFLOW A) No power to the fans Check power supply to the fan motors
B) The filters are dirty Shake dust out of the cartridge and clean
with a vacuum cleaner. Change filter if
blocked. Check correct setting of the dirty
filter pressostat.
C) The airflow is obstructed Read the section on Air Distribution
D) Intervention of fan thermal
protection.
Check the resistance of the fan windings.
Re-set then measure voltage and current.
E) The pressure drop in the air distribution
system (grilles, ducts, etc.) is too high.
1) Check the air distribution system
2) Increase fan speed (see Fan Speed Regulation)
REFRIGERANT CIRCUIT
PROBLEM POSSIBLE CAUSE CHECK / REMEDY
HIGH COMPRESSOR OUTPUT
PRESSURE
A) Non-condensable air or gas in the
circuit, with bubbles in the flow sight
glass; supercooling of the liquid is
high.
Evacuate the refrigerant circuit and re-
charge
B) Airflow is insufficient or air in the
remote condenser is too warm.
1) Check fan operation and rotation direction
in the remote heat exchanger. (See
condenser/radiator instruction manual).
2) Remove any obstructions from the remote
condenser with compressed air or water.
C) Too much refrigerant in the circuit;
condenser partially flooded.
Refrigerant supercooling too high at
condenser output
Remove some refrigerant from the circuit.
HIGH PRESSURE PRESSOSTAT
INTERVENES
A) The condensation pressure control
system is not functioning efficiently
1) Check condenser fan; re-set or replace
the faulty fans;
2) Check setting and function of the RVC/e.
speed regulator (see Regulation of
condensation pressure)
B) High system output pressure See High compressor output pressure
LOW COMPRESSOR OUTPUT
PRESSURE
A) The condensation pressure control
system is not working (see
microprocessor control instruction
manual).
1) Check the function and setting of the
condenser fan pressostat and speed
regulator
B) Intake pressure too low See Low Compressor Intake Pressure.