Carrier DB-S Series, Use & Maintenance Instructions

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9.5 Electronic controller alarms
When a fault is detected,the red Led in key (4) will be lit and a fault code displayed on
the screen (5).This code enables a speedy identification of the problem and should be
reported when making the service call.(The audible alarm will also sound if fitted).
High temperature alarm
The label (HI) and the cell temperature are intermittently displayed one after the
other.
Alarm relay activated
Causes: - The door has been opened too frequently
- The product load in the cell exceeds cell capacity
- The temperature of the products stored in the cell is too high
- Refrigeration system malfunction
Low temperature alarm
The label (LO) and the cell temperature are intermittently displayed one after the
other.
Alarm relay activated
Causes: -Electronic control unit malfunction
Solution: -Call technical assistance service
Ambient temperature sensor alarm
The label (EO) appears on the digital display.
Alarm relay is active
Causes: -The sensor is not connected
Solution: -Replace sensor
Evaporator sensor alarm
The label (E1) and the cell temperature are intermittently displayed one after the
other.
Causes: -The sensor is not connected
Solution: -Replace sensor
High pressure alarm
The label (HH) and the cell temperature are intermittently displayed one after the
other; led (4) lights up each time the high pressure switch is tripped.
If the high pressure switch is tripped more than 10 times in a one-hour period, the
label (PP) and the cell temperature will appear intermittently one after the other
on display (5), while the alarm relay will be activated together with led (4).
Room light switch, evaporator & condenser fan OFF.
To reset the alarm, disconnect the refrigeration unit, wait for a few seconds, then
restore connection.
Causes: -Ensure that the condenser fan is working properly
-Ensure that the condenser is clean.
9.6 Emergency system In case of fault or malfunctioning of the electronic control panel,if a short-term
replacing is not possible, an “EMERGENCY SYSTEM” can be used to keep the
unit running until a new control panel may be installed.
The “EMERGENCY SYSTEM” consists of a terminal board sited on the control
panel, fitted with 4 terminals , as shown in picture 15.
Proceed as follows to use the system:
1) Switch the electronic control panel off by pressing the key ON/OFF (10).
N.B.: The electronic control panel should remain in this condition during the whole
emergency period.
2) Switch the unit off.
3) Connect a thermostat (6 inductive Amps.) to the terminals E1 and E2 (Fig. 16).
4) Bridge terminals E2 and E3 as well as terminals E3 and E4 (Fig.16).
5) A wire comes out from nr. 30 on the card; it is welded in the card an connented
to terminal 4. Disconnect it and let it free.
6) Enter the thermostat bulb inside room.
7) Adjust the 'stat at the required temperature and switch the unit on.
E4 E3 E2 E1
Fig.15