• 61 •BALTIC-IOM-0412-E / Service manual
SERVICE DIAGNOSTIC
Refrigeration
Fault Possible cause and symptoms Solution
LP problems and
LP cut outs
Refrigerant charge too low
Measure the superheat and sub-cooling:
Good if 5°c<sc<10°c and 5°c<sh<10°c
Bad if sc>10°c and sh too low
Check superheat adjustment and charge unit (a leak check
must be carried out)
In heat pump mode the temperature
difference between t outdoor and tevap. (dew)
is too high
5°c < delta t < 10°c excellent
10°c < delta t < 15°c acceptable
15°c < delta t < 25°c too high
If too high check the coils are clean or check coil internal
pressure drop between the liquid line and the suction line
Good if < 3bar
Too high if > 3bar (coil blocked)
Refrigeration circuit blocked in distribution
Stop the fan and create icing of the coil.
Check all circuits freeze evenly across the whole surface of
the coil
If some parts of the coil do not freeze this could indicate a
problem with the distribution
Liquid line drier blocked. High temperature
difference between inlet and outlet of the drier
Change fi lter drier
Contaminant in the expansion valve
Attempt to free the valve adjusting element by freezing the
valve and then heating the thermostatic element. Replace the
valve if necessary
Expansion valve not adjusted properly Adjust the expansion valve
Ice plug in the expansion valve.
Heat the main body of the valve. If the LP increases and then
decreases gradually, empty the circuit and replace the drier.
Incorrect insulation of the thermostatic bulb of
the expansion valve
Superheat too low: adjust superheat
Move the thermostatic element along the pipe
Insulate the thermostatic element of the valve
Low pressure switch cut out point too high
Check the cut out pressure of the low pressure switch: it must
be 0,7+/- 0,2bar and must closes at 2,24 +/- 0,2 bar
LP cut out due to not enough defrost on heat
pumps
Adjust the CLIMATIC™ settings to extend the defrost cycles
or shorten the time between defrosts
HP problems and HP cut outs
Incorrect airfl ow rates
Heat pump mode:
check the fi lter before the indoor coil
measure and estimate the airfl ow rate
increase the speed of the fan
Cooling mode:
check the condenser fan (amps)
Moisture or contaminants in the system
Summer operation
Several hours after the unit has stopped, check the
correspondence between the measured pressure and the
outdoor temperature
To Next Page
Loading...
Need help?
General
