MAINTENANCE DIAGNOSTIC
e-BALTIC-IOM-2020.12-EN
79
MAINTENANCE DIAGNOSTIC
REFRIGERATION
FAULT
POSSIBLE CAUSE AND SYMPTOMS
SOLUTION
LP FAULT
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 > 3 bar (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
Change filter drier
Electronic expansion valve problem
Check the wiring
Low pressure shutdown due to ice
accumulation on the batteries
Check the defrost cycles. (cloud supervision
advised)
