MCA
38
RG66001206 - Rev 03
È severamente vietata la riproduzione anche parziale di questo manuale / All copying, even partial, of this manual is strictly forbidden
SYMPTOM
D
The compressor
does not start
because the
maximum
pressure switch
has tripped
E
The compressor
does not start
because the
minimum
pressure switch
has tripped
F
The fans do not
start
Cooling
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Heating
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Who can take
corrective action
U
= User
S
= specialised
personnel
S
S
U
S
U
S
S
S
S
S
U
S
S
S
S
S
S
S
S
S
S
S
S
Possible
control panel
indication
H1
H1
H1
H1
H1
H1
H1
H1
L1
L1
L1
L1
L1
L1
L1
L1
L1
L1
H1
L1
H1
L1
H1
L1
H1
L1
H1
L1
Probable cause
Pressure switch failure
Excessive refrigerant charge
Finned coil obstructed, insufficient air flow
Fan not working
Water circulation pump blocked
Water circulation pump defective
Presence of incondensable gas in the cooling
circuit
Refrigerant filter clogged
Pressure switch failure
Unit completely empty
Finned coil obstructed, insufficient air flow
Water circulation pump blocked
Water circulation pump blocked defective
Presence of frost on the evaporating coil
Evaporator fan not working
Refrigerant filter clogged
Expansion valve is not working properly
Presence of humidity in the cooling circuit
Fan contactor deenergized (MCA only)
No power output by the fan speed control card
(only MCA H or MCA with condensation control)
The fan's internal thermal protection has tripped
Fan motor defective
Loose electrical connections
Possible remedy
Check and replace
Discharge the excess gas
Remove dirt from the coil and any
obstacles to air flow.
See item F
Release the pump
Check the pump and replace it if
necessary.
Recharge the circuit after having
drained and evacuated it
Check and replace
Check and replace
See item G
Remove dirt from the coil
Release the pump
Check the pump and replace it if
necessary.
See item O
See item F
Check and replace
Check and replace if necessary
Replace the filter and, if necessary,
dry out the circuit and recharge
Check the voltage at either end of the
contactor coil and verify the continuity
of the coil itself
Check the contacts and replace if
necessary
Check the fan conditions and the air
temperature while the unit is running.
Check and replace if necessary
Check and fasten securely
11
TROUBLESHOOTING
