Operationg Conditions; Putting Into Operation And Function; General Remarks; Indicator Elements - Pfannenberg DTT 601 Serie Instrucciones De La Instalación Y Del Uso

Door contact:
The door contact is supplied form the cooling unit with an extra-low
voltage (<20V, 20 mA).
• In order to avoid any disruptive influences, it is recommended
that a sheathed cable with twisted pair leads be used. The screen
can be secured on one side to the PE connection point provi-
ded on the cooling unit.
• If the use of sheathed cables is not possible, during installation of
the cables it must be ensured that they are not routed in the imme-
diate vicinity of potential interference sources (e.g. supply lines, com-
ponents with relatively high electromagnetic emission).
WARNING: No external voltage may be applied.
If no door-contact switch is used, the connecting contacts
are to be bridged.
Centralised fault indication:
For connection of the fault signal line there are 2 connection contacts
and/or connecting lines available (see connection diagram on the
underside of the housing)
The installation of the fault signal line is not subject to any special
requirements.
WARNING: The contact may be loaded with
max. 230 V, 1A.
Multimaster:
(Optional, only for units with Multi-Controller)
To connect the multimaster cables there are in each case 2
connecting contacts (input and output-end) available (see connection
diagram on the underside of the housing).
The contacts are supplied with low voltage (< 20 V, 20 mA) from the
cooling unit.
WARNING: No external voltage may be applied.
• In order to avoid any disruptive influences, it is recommended
that a sheathed cable with twisted pair leads be used. The she-
ath can be connected at both ends to the PE terminal provided
on the cooling unit for the purpose.
• If the use of sheathed cables is not possible, during installation of
the cables it must be ensured that they are not routed in the imme-
diate vicinity of potential interference sources (e.g. supply lines, com-
ponents with relatively high electromagnetic emission).
• A maximum of 20 units may be controlled over the bus.
Block diagram of the Multimaster wiring
9 Operating Conditions
• Voltage must be within ± 10 % of the value indicated.
Frequency must be within ± 3 Hz of the value indicated.
• Ambient temperature must be below 55 °C (for options see ac-
companying supplement sheet).
• Use the unit such that the cooling capacity suits the actual de-
mand.
• Use refrigerant as indicated only.
• Use genuine spare parts only.

10 Putting into operation and function

10.1 General remarks

The cooling unit is provided with an electronic control system. The
drawn-in switch cabinet internal air temperature is measured by a tem-
perature sensor. By means of a DIP switch on the control board, diffe-
rent switch cabinet temperatures as well as upper limit temperatures
can be selected (see accompanying supplement sheet). For units
with Multi-Controller, selection is made from a control unit. E x c e e -
ding the limit temperature generates an alarm. For units with Multi-
Controller, the lower temperature limit can also be monitored.
085 408 097a
Warning!
Ambient conditions and temperature in the switch cabinet must
be in accordance with the values indicated in the accompa-
nying supplement sheet.
Warning! Too little heat transfer at the heat exchan-
ger in the external circuit (condenser).
The cooling unit may only be operated with cover, otherwi-
se heat dissipation at the condenser is not sufficient, and
the cooling unit may be damaged.
Immediately after the switch-on of the service voltage, the
unit goes into the start-up/test mode. After that the evapo-
rator fan continues to run. Compressor and condenser fans
run on as required (the temperature of the switching thres-
hold (T ) has been reached, or are switched off (tempera-
set
ture lower than switching threshold (T

10.2 Indicator elements

The cooling unit with standard controller has an operation indicator
with an LED in the outside cover of the unit.
If the light of this indicator remains on when the supply voltage is ap-
plied it shows that the unit is in the normal operating mode. If a fault
occurs or if the unit is in the start-up or test mode, this indicator lights
up in various flashing sequences which make it easier to diagnose
fault in the unit (see Sections 10.4 and 13).
The cooling unit with multi-controller has an operation indicator
with the help of which the unit parameters can be set (for more
details see the separate operating instructions for the multi-cont-
roller).

10.3 Test mode / start-up

The test mode is basically activated after renewed connection of
the supply voltage and is independent of the instantaneous ambient
conditions when the door contact is closed.
First of all the unit runs through a start-up mode lasting 30 seconds
which is followed by a test mode lasting 30 seconds.

10.4 Unit characteristics

Modus Time curve Characteristics
Start-up t = 0s - < 30s No function
mode t = 30s
t = 32s
Test mode t >34s – 64s
The start-up mode is always additionally activated when the door
limit switch is closed (see Sections 10.5)
)).
set
Internal fan start up
External fan and
compressor start up
Flashing sequence of the
status indicator:
"off-dark-light-dark-off".
Fault signal contact is closed.
Compressor and fans
remains in operation during
the period. Flashing sequence
of the status indicator:
"off-dark-light-dark-off".
Fault signal contact is open.
Should a fault arise during
the test mode, the unit goes
into the fault mode and the
status indicator lights up
according to the fault state
(see chapter on Fault
diagnosis)
13