Instruction manual

OPERATION AND MAINTENANCE MANUAL
Wall Mounted 0121…0661
28 (32)
Monobloc Wall Mounted Unit - WMA/WMF 0121-0181-0251-0281-0331-0551-0661 - Rev. 2.0. - Date: 18-07-2000 EN
REFRIGERANT CIRCUIT
PROBLEM POSSIBLE CAUSE CHECK/REMEDY
HIGH COMPRESSOR INTAKE
PRESSURE
A) Heat Load greater than expected. Check the consistency of the room thermal load;
check, in the presence of strong dehumidification,
the airflow and the external conditions; check the
amount of outside air draw.
B) Airflow pressure too high. See “HIGH COMPRESSOR OUTPUT
PRESSURE”.
C) Circuit refrigerant overload Remove the refrigerant from the circuit.
D)Return of liquid refrigerant to the
compressor intake.
Check that the overheating of the thermostat valve
is correct (approx 5-8°C); check that the valve
sensor bulb has not lost its refrigerant charge and
is well positioned, fixed and isolated.
LOW COMPRESSOR INTAKE
PRESSURE
A) Room temperature is too low. See “ROOM TEMPERATURE IS TOO LOW”.
(and formation of frost in the coil) B) Air flow is too low or absent. SEE “LOW AIR FLOW”.
C) Refrigerant filter is blocked. Check the refrigerant filter.
D) Thermostat Valve is un-set or faulty. Check that the overheating of the thermostat valve
is correct (approx 5-8°C); check that the valve
sensor bulb has not lost its refrigerant charge and
that it is correctly positioned, fixed and isolated.
E) Insufficient refrigerant load. Check for any leakage and restore the load to
measure a sub-cooling of the condensor liquid
outlet of 3-5°C.
INTERVENTION OF THE
PRESSOSTAT BP
(low compressor intake pressure)
A) Thermostat valve is un-set or faulty. Check that the overheating of the thermostat valve
is correct (approx 5-8°C).
B) filter cartridge is dirty. deidratore Check that the cartridge dehydrator filter doesn’t
need to be replaced; the difference between the
air temperature measured before and after the
filter must be less than 2°C.
C)Output pressure is too low. see “LOW COMPRESSOR OUTPUT
PRESSURE” .