Code +030220811- rel. 1.0 – 26.04.2007
26
PROBLEM CAUSE SOLUTION
LOP protection disabled
Set a LOP integration time greater than 0 sec.
LOP protection ineffective
Make sure that the LOP protection threshold is at the required
saturated evaporation temperature (between the rated
evaporation temperature of the unit and the corresponding
temperature at the calibration of the low pressure switch) and
decrease the value of the LOP integration time.
Solenoid blocked
Check that the solenoid opens correctly, check the electrical
connections and the operation of the control relay.
Insufficient refrigerant
Check that there are no bubbles of air in the liquid indicator
upstream of the expansion valve. Check that the subcooling is
suitable (greater than 5 °C); otherwise charge the circuit.
The valve is significantly undersized Replace the valve with a larger equivalent.
Stator broken or connected
incorrectly
Disconnect the stator from the valve and the cable and measure
the resistance of the windings using an ordinary tester.
The resistance of both should be around 36 ohms. Otherwise
replace the stator. Finally, check the electrical connections of the
cable to the driver (see paragraph 5.1).
The unit switches
off due to low
pressure during
control (only for
units with
compressor on
board)
Valve stuck closed
Use manual control after start-up to completely open the valve. If
the superheat remains high, check the electrical connections
and/or replace the valve.
Solenoid blocked
Check that the solenoid opens correctly, check the electrical
connections and the operation of the relay.
Insufficient refrigerant
Check that there are no bubbles of air in the liquid indicator
upstream of the expansion valve. Check that the subcooling is
suitable (greater than 5 °C); otherwise charge the circuit.
The valve is significantly undersized Replace the valve with a larger equivalent.
Stator broken or connected
incorrectly
Disconnect the stator from the valve and the cable and measure
the resistance of the windings using an ordinary tester.
The resistance of both should be around 36 ohms. Otherwise
replace the stator. Finally, check the electrical connections of the
cable to the driver (see paragraph 5.1).
The showcase does
not reach the set
temperature,
despite the value
being opened to
the maximum (for
multiplexed
showcases only)
Valve stuck closed
Use manual control after start-up to completely open the valve. If
the superheat remains high, check the electrical connections
and/or replace the valve.
The driver in pLAN or tLAN
configuration does not start control
and the valve remains closed
Check the pLAN / tLAN connections. Check that the pCO
application connected to the driver (where featured) correctly
manages the driver start signal. Check that the driver is NOT in
stand-alone mode.
The showcase does
not reach the set
temperature, and
the position of the
valve is always 0
(
for multiplexed
showcases only)
The driver in stand-alone
configuration does not start control
and the valve remains closed
Check the connection of the digital input. Check that when the
control signal is sent that the input is closed correctly. Check that
the driver is in stand-alone mode.
CAREL reserves the right to make modifications or changes to its products without prior warning.
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