Checking The Supply, Safety, Return And Dhw Temperature Sensors; Cables - Buderus Logamax plus GB162-80 kW Service Instructions Manual

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 Disconnect the DHW temperature sensor plug [1].
 Set the multimeter to "Measure resistance" [2].
 Measure the electrical resistance of the DHW temperature
sensor [3].
 Measure the electrical resistance over the DHW temperature
sensor to ground. This electrical resistance must be infinite.
 Use a digital contact-type thermometer to measure the tem-
perature in the vicinity of the corresponding sensor.
 Compare the resistance values measured at the tempera-
tures measured to the values in section 134.
 Replace the relevant sensor if the reading fluctuates by more
than 10 % with respect to the reference value (e.g. infinitely
high resistance in the event of a line break or resistance of
Ω
0 in the case of a short circuit).
 Attach the relevant sensor plugs.
 Close the boiler door and install the casing of the pump group
in reverse order of removal.
 Switch on the power supply to the heating system, see
section 79.
Logamax plus GB162-80 kW/100 kW - Subject to modifications resulting from technical improvements!
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section 94 Checking the supply, safety, return and DHW
temperature sensors; cables
H
DANGER OF FATAL ACCIDENT
A
due to electric shock!
DAMAGE TO THE INSTALLATION!
To prevent damage, do not insert the multimeter
measuring electrodes too far into the holes of the plug-
and-socket connection.
 Switch off the power supply to the heating system, see
section 72.
 Open the boiler door as instructed in section 73.
 Remove the UBA 3 as instructed in section 82.
 Remove the cover from the connection tray, see section 114.
 Disconnect the supply temperature sensor plug,
see section 93, [1].
 Set the multimeter to "Measure resistance" [1].
 Check the supply temperature sensor cable for breaks.
The electrical resistance measured separately for every wire
Ω
must be approx. 0 [2]. Measure between the plug and the
black contacts (low-voltage connector pins 13 and 14) on the
UBA 3 mounting base [3].
 Check the supply temperature sensor cable for internal short
circuiting. The electrical resistance, measured between two
random wires, must be infinite.
 Measure the electrical resistance over the supply tempera-
ture sensor cable to ground. The electrical resistance must
be infinite for every individual wire.
 Disconnect the safety temperature sensor plug as instructed
in section 93, [1].
Actions
81-pin low-voltage connector
16-pin high-voltage connector
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