Technical Bulletin
Identification: |
All cooling equipment |
Bulletin no: |
VTX2004-08 |
Date: |
11-11-04 |
Issuer: |
Customer Support Dept. |
Factory: |
Villotta (Italy) |
Subject: |
How to check if a PROBE is working or not |
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Model: |
All appliances. |
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Problem: |
The display doesn’t show any temperature or a wrong |
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temperature. |
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Reason: |
The probe is bad connected or out of service |
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Action in |
All the appliances are tested at the end of the product line |
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Factory: |
before packaging. |
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Action in |
The service should be able to do a quick diagnostic and |
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Field: |
understand if the probe has faulted or not (see details below). |
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W H A T |
T O |
D O |
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check the electrical connection into the |
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check the connection between the probe |
check the position of the probe; check if |
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check the resistance (Ω) of the probe with a |
and the connector of the dgt (or electronic) |
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electrical box; |
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the real probe position is according to its |
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check if the dgt (or electronic) control has |
multimeter (values according to the |
control: if the terminal wirings of the probe |
label (def=defrost=evaporator; cell=inside |
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a good connection to the power supply |
amb.temp. -see the attached table-) |
aren't well insulated and properly |
the cell; cond=condenser; etc.) |
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connected, a short-circuit can happen |
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blank (with alarm on) |
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DISPLAY |
wrong temperature |
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(with no alarms running) |
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wrong temperature |
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(with alarm on) |
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R |
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bad connection |
probe miscalibrated, |
short-circuit in probe |
wrong installation |
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open-circuit in probe |
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ELECTROLUX PROFESSIONAL |
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p. 1 of 4 |
VIA 1° MAGGIO, 2 – 33089 VILLOTTA (PN) – ITALY |
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TELEPHONE: |
TELEFAX: |
E-MAIL: |
+ 39 0434 637609 |
+ 39 0434 630 472 |
gabriele.dal-bianco@electrolux.it |
Technical Bulletin
Identification: |
All cooling equipment |
Bulletin no: |
VTX2004-08 |
Date: |
11-11-04 |
Issuer: |
Customer Support Dept. |
Factory: |
Villotta (Italy) |
Instruments requested for diagnostic: digital multimeter and a standard tool-box.
“Resistance – Temperature” table (*)
Appliance type |
Cabinet&counters, BC&F and cold self-service |
hot self-service |
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Probe type |
2K7 |
10K |
10K SEMITEC 103AT |
NTC M891 22K |
Temperature [°C] |
Ohm [Ω] |
Ohm [kΩ] |
Ohm [kΩ] |
Ohm [kΩ] |
-40 |
100÷86 |
340÷320 |
196÷181 |
--- |
-30 |
53÷45 |
188÷165 |
115÷107 |
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-20 |
30÷23 |
103÷91 |
70÷65 |
258÷247 |
-10 |
18÷13 |
59÷52 |
44÷41 |
144÷135 |
0 |
11÷8 |
36÷31 |
28÷26 |
81÷76 |
10 |
6÷4 |
20÷18 |
19÷17 |
50÷44 |
20 |
3.5÷3.0 |
13÷11 |
13÷11 |
29÷27 |
25 |
3.0÷2.5 |
11÷9 |
11÷9 |
23÷21 |
30 |
2.5÷2.0 |
9÷7 |
9÷7 |
18÷16 |
40 |
--- |
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12÷10 |
50 |
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8÷6 |
When ambient temperature is around 25°C, a good (10K Semitec 103AT) probe should have a resistance around 10 kΩ, it means that the multimeter has to show a value of about 9÷11 kΩ
(according to the resolution of the instrument and to the real ambient temperature).
(*) see the following table to find the probe properties.
ELECTROLUX PROFESSIONAL |
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p. 2 of 4 |
VIA 1° MAGGIO, 2 – 33089 VILLOTTA (PN) – ITALY |
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TELEPHONE: |
TELEFAX: |
E-MAIL: |
+ 39 0434 637609 |
+ 39 0434 630 472 |
gabriele.dal-bianco@electrolux.it |
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