Panasonic U-16GE2E5 Test Run Manual page 12

● Device ground check
Is earth ground securely obtained?
● If an error is found in the wiring connections, the following check procedure allows you to quickly identify the
location of the error. When performing the check procedure, it is convenient if you have a drawing showing the lay-
out of devices and wiring routes to refer to.
· In systems that are comprised of multiple wiring systems linked together, you can quickly identify the loca-
tion of the error by removing the 'link' and determining whether each individual system is good or not good. A
warning in a certain system does not necessarily mean that the cause of the error is in that system. Check the
indoor/outdoor control wires of all systems, since the abnormality may be in the wiring of a system other than
that where the warning is triggered.
Wire connecting the systems
· When the wiring route is divided into segments by the terminal block of each unit, it is advisable to check the
wiring connection on a segment by segment basis, starting with the segment between the outdoor unit and in-
door unit 1, then the segment between the indoor units 1 and 2, and so on. This allows you to fi nd the location of
the connection failure between units.
Indoor 1
Outdoor
unit
· If the device contains operation wire branched from indoor/outdoor control wire, there may be failure in the
indoor/outdoor control wire before branches.
Outdoor
unit
Ground faults or short circuits can also occur in the indoor/outdoor control wiring before branches.
● If communication error occurs, check the sensor's ground fault.
● Check sensors (thermistor) ground fault.
Before checking, turn off the device and remove target sensor from the board before performing measurement.
6. Ground fault check
6-1
6-2
Outdoor
unit 1
Outdoor
unit 2
Outdoor
unit 3
Indoor 2 Indoor 3
First, check the wire between the outdoor unit and indoor unit 1.
Then, check the wires between 2, 3, and so on in order.
Indoor 1 Indoor 2
Measure the resistance between one end of the indoor/outdoor
control wire and the point of ground screw, as well as the
resistance between the other operating line end and the point of
the ground screw. Are both measured resistance values in MΩ
unit (infi nite)?
Replace thermistor and wiring
II - 4
Indoor Indoor Indoor
Indoor Indoor Indoor
Indoor Indoor Indoor
Indoor 3
Branch indoor/outdoor
control wire
Wire connecting the systems
Yes Good
No 6-2