LAE BIT20A22 Instructions For Installation And Use

INSTRUCTIONS FOR INSTALLATION AND USE.
BIT20A22
BIT20B22
We thank you for choosing an LAE controller. Before proceeding to the installation of the BIT20, please read this instructions sheet carefully; only
in this way you will obtain maximum performances and safety.
1. INSTALLATION
1.1 The BIT20 has got a size of 110x87x55 mm; it must be secured to the panel with three screws or rivets to be inserted into the suitable
slots. Protection is IP30, therefore please locate the unit in a position ensuring that no liquid infiltrates and damages the unit.
1.2 The unit must work with ambient temperature between -10°...+50°C and 15%...80% relative humidity. To reduce the effects of electro-
magnetic interference, locate the probe cables and the unit as away as possible from power lines.
1.3 Probes, power supply and outputs must be connected strictly according to the indications appearing on the board; the cables can pass
through the hole on the unit side. For supply voltage and maximum loads please read the label inside the enclosure.
1.4 Probe TA measures air temperature and is used for temperature control. Probe TE measures the evaporator temperature and must be
located in a place where the maximum frost growth occurs.
1.5 The flat cable of the remote display must pass through the suitable opening of the lid that also keeps the cable locked. This operation
must be performed after the lid has been lifted upwards completely.
Caution: where delicate or valuable products have to be maintained under strict conditions, please use a different controller for limit and alarm
functions.
2. CONTROL PARAMETERS
The adaptation of the BIT20 to the system that it controls is achieved through the control parameters. BIT20B allows parameters setting
through the keypad on BIT12RU remote unit. Differently, BIT20A has been thought to provide two alternative setting methods of the control
parameters. The first one, like in the BIT20B, by means of keypad, the other method is new and allows to select all main parameters through
the combination of dipswitches located on the control unit. Operating mode selection is made via MEMORY/SELECTORS dipswitch.
2.1 M . In this operating mode, all control parameters are adjustable and saved into permanent memory during the SETUP. The SETUP
EMORY
function is accessible by pressing
display its value by pressing
Exit from the SETUP takes place automatically after 15 seconds of no key activation.
In MEMORY mode, without having to enter the SETUP, the setpoint value SP can always be displayed by pushing key
within the SL and Sh limits via
(1) . In this operating mode, the dipswitches and some default parameters determine control. The adjustable parameters are:
2.2 S
ELECTORS
A) Setpoint: to select the setpoint range, move just one of the range selectors to YES (-35...-20; -19...-4; -3 ...+12°C). After having done
this, by moving one or more of the setpoint modification selectors to YES (+
minimum limit, obtaining in this way the actual setpoint value (see Figure 1).
B) Hysteresis: the on switching differential starts from 1°K minimum to which, through the relevant switches, you may add up to 7°K. The
thermostat hysteresis is therefore adjustable from 1 (all NO) to 8°K (all YES) in 1°K steps.
C) Defrost frequency: the number of defrosts per 24 hours ranges from a maximum of 7 and a minimum of 1 per day. Setting all switches
to NO excludes defrost.
D) Defrost duration: duration ranges from a fixed minimum of 10 minutes (all switches NO) to a maximum of 80 minutes (all YES) in 10
+ + for 4 seconds. Scroll the parameter list via keys
and modify it via + or
1 SP thermostat Off switching temperature
2 SL minimum programmable temperature
3 Sh maximum programmable temperature
4 hy thermostat On switching hysteresis
5 cr minimum compressor rest time
6 cF compressor safety run in case of probe failure
7 dF number of defrosts within 24 hours
8 dt maximum defrost duration
9 dL defrost limit temperature
10 dM defrost mode
11 dr drain time
12 th display control during defrost
13 to offset of displayed temperature
14 tS slowdown of displayed temperature
+ or .
. The parameters available in the BIT20 are the following:
), you add the value reported on their side to the setpoint range
and until you achieve the desired one,
[00=40% ... 01=100%]
[0=off cycle; 1=electric; 2=hot gas]
[0='TA' ... 60 minutes='dF']
and programmed
[SL ... Sh]
[-35 ... Sh]
[SL... +15°C]
[+1 ... +8°K]
[0 ...4 minutes]
[0 ... 12]
[1 ... 90 minutes]
[+1... +20°C]
[0... 10 minutes]
[-9... +9°K]
[0 ... 20]