Carrier 50FF Series - Control and Analysis of Breakdowns

61
15 - CONTROL AND ANALYSIS OF BREAKDOWNS
Symptom Cause Solution
Evaporation pressure very
high in relation with the air
inlet
a) Charge excess
b) High air temperature
c) Compressor suction not air tight
d) Cycle reversing valve in middle position
a) Collect refrigerant
b) Verify overheating
c) Verify compressor state and replace
d) Check that the valve is not clogged. Replace if
necessary
Very low condensation
pressure
a) Gas lack
b) Compressor suction not air tight
c) Cycle reversing valve in middle position
d) Liquid circuit plugging
a) Search for leaks, complete charge
b) Verify compressor state and replace
c) Check that the valve is not clogged. Replace if
necessary
d) Verify the dehydrating fi lter and expansion valve
Condensation pressure very
high in relation to the air
outlet, high switch cutoff
a) Insuffi cient air fl ow
b) Air inlet temperature very high
c) Dirty condenser (does not exchange)
d) Much refrigerant charge (fl ooded condenser)
e) The condenser fan is broken down
f) Air in the cooling circuit
a) Verify the air circuits (fl ow, fi lter cleanliness...)
b) Verify the control thermostat readjustment
c) Clean it
d) Collect refrigerant
e) Repair
f) Make vacuum and charge
Evaporation pressure too low
(low pressure safety cut-off )
a) Low fl ow in evaporator. Air recirculation
b) Frozen evaporator
c) Liquid line as diff erent temperatures at fi lter inlet and
outlet
d) Gas lack
e) Very low condensation pressure
f) Evaporator fan broken down
a) Verify the air circuits (fl ow, fi lter cleanliness...)
b) Verify defrost
c) Replace fi lter
d) Search for leaks, complete charge
e) Temperature of air or water in condenser very low
(air or water fl ow very high), adjust fl ow
f) Repair
Compressor does not
start, does not make noise
(humming)
a) No power
b) The contacts of a control element are open
c) Timing of anti cycle short does not allow the starting
d) Open contact
e) Contactor coil burnt
f) Indoor klixon open
a) Check diff erential, fuses
b) Verify the safety chain of the electronic control
c) Verify electronic control
d) Replace
e) Replace
f) Wait for reactivation, verify current absorbed
Compressor does not start,
motor sounds intermittently
a) Electrical power supply very low
b) Power cable disconnected
a) Control line voltage and locate voltage drop
b) Verify connections
Repeated compressor starts
and stops
a) Because of high pressure
b) Control diff erential too short (short cycle)
c) Insuffi cient gas, cut-off because of low pressure
d) Dirty or frosted evaporator
e) The evaporator fan does not work, cuts off the low
switch
f) Expansion valve damaged or clogged by impurities
(cuts off the low pressure safety)
g) Dehydrating fi lter clogged (cuts off the low pressure
safety)
a) Verify charge
b) Increase diff erential
c) Search for leak, reload unit
d) Clean, verify evaporator air circuit
e) Replace or repair
f) Replace, as well as fi lter
g) Replace
The compressor makes a
noise
a) Loose attachment
b) Oil lack
c) Compressor noise
a) Fix
b) Add oil to recommended level
c) Replace
Noisy operation a) Unit installed without antivibration protection a) Place base over shock absorbers
Cycle reversing is not carried
out:
- No defrosting
- Does not change winter -
summer cycles
a) Electrical fault
b) Inversion valve coil defective
c) Defrost method not working
d) Cycle reversing valve in middle position
e) Control fault
a) Locate and repair
b) Replace
c) Verify parameters
d) Tap with running compressor. Replace if necessary
e) Locate and repair
Alarm or reading error in the
humidity probe (with enthalpic
control)
a) Dirt in the humidity sensor a) Disassembly the probe encapsule.
Proceed to clean the sensor with some soft cotton
element and non-abrasive fl uid, without pressing it.
Reassemble the casing, checking that the cable is
in contact externally with the metallic mesh.